Golf ball compositions with improved temperature performance, heat resistance, and resiliency

ABSTRACT

Golf ball compositions, and components formed therefrom, including trifunctional materials, such as trifunctional isocyanates, polyols, and amines, that have improved performance and durability characteristics, e.g., improved heat resistance, improved resiliency, and dimensional stability.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/820,124, filed Apr. 8, 2004, now U.S. Pat. No. 7,226,983, the entiredisclosure of which is incorporated by reference herein.

FIELD OF THE INVENTION

The invention relates to golf ball components including trifunctionalmaterials that have improved performance and durability characteristics.In particular, the present invention is directed to various golf ballcomponents, e.g., golf ball covers, cores, and intermediate layers,formed from trifunctional isocyanates, polyols, and amines that haveimproved resiliency at non-optimal temperature conditions. In addition,the present invention relates to golf ball components formed fromtrifunctional materials that have improved heat resistance over golfball components not including trifunctional materials.

BACKGROUND OF THE INVENTION

Golf ball components are formed from a variety of compositions. Forexample, golf ball cores, intermediate layers, and covers may be formedfrom materials ranging from balata to ionomer resin to polyurethane orpolyurea. Manufacturers constantly experiment with the differentmaterials for use in the various golf ball layers in order to providegolf balls that have desirable aerodynamic properties, soft “feel”, andincreased durability. Therefore, depending on the materials used toconstruct the golf ball components, the golf ball may have longdistance, but poor durability, or have good durability, but a hard“feel”.

Golf balls function partly as a result of their ability to transferkinetic energy of a moving golf club head to the golf ball. The abilityto transfer this kinetic energy is related to the modulus of elasticityof the various polymeric compounds that make up the components of thegolf ball in addition to the material properties of the golf club.Because the modulus of elasticity varies with temperature, high and lowtemperatures will typically effect the performance of the golf ball. Infact, the coefficient of restitution (COR), which is the ratio of theoutbound or rebound velocity to the incoming or inbound velocity, may beused, at least in part, as an indicator of performance at varioustemperatures. And, as known to those of ordinary skill in the art, theCOR of most golf balls decreases as the temperature of the environmentdecreases. Thus, golfers in cold climates may experience shorter drivingdistance and a “hard feel” due to the COR loss of the golf ball atnon-optimal temperatures.

For practical purposes, the optimum temperature for maximum drivingdistance and a “soft” feel is about 59° F. to about 95° F. Depending onthe season and the climate, golf balls can be well below this optimumtemperature range. Generally, the higher the temperature within a givenrange, the higher the modulus of elasticity, and, conversely, the lowerthe temperature, the lower the modulus of elasticity. In other words, asthe temperature drops, golf balls generally become stiff and usuallycannot be driven as far as when they are warm. In fact, golf ballsstored in an unheated area may have a ball temperature of 32° F. orless, which may have a dramatic effect on the driving distance and feelof the golf ball.

One way to avoid playing with a golf ball that has a temperature outsideof the optimum range is to manufacture the golf ball with a qualitativetemperature indicator. Examples of golf balls having such temperatureindicators are disclosed in U.S. Patent Publication No. 2003/0109329.Another way to compensate for non-optimum ball temperatures is to use aportable golf ball warmer, such as the one disclosed in U.S. Pat. No.5,915,373.

Still another attempt at reducing the effect of non-optimal temperatureson driving distance and golf ball feel is to use a golf club thatcompensates for various changes in stiffness of a golf ball. U.S. Pat.No. 5,899,818 discloses a golf club head having temperature-variableimpact properties using a shape memory alloy that becomes stiffer athigher temperatures and more elastic at lower playing temperatures.While these methods allow a player to use a golf ball in non-optimalplaying conditions and may allow the golfer to achieve adequatedistance, they require special equipment to do so.

Yet another known problem with conventional golf balls is thedegradation of the materials used to form the golf ball components atelevated temperatures. For example, wrinkling of the golf ball componentmay occur at about 50° C. In fact, even the most advanced light stablepolyurethane and polyurea compositions have been shown to be susceptibleto heat degradation during additional processing steps, e.g., coatingand marking, and upon storage in non-optimal temperatures.

With regard to material degradation at elevated temperatures, severalmanufacturers have attempted to compensate for any golf ball coverdegradation upon application of heat by using coatings havingcontraction and expansion properties. For example, U.S. Pat. No.5,816,943 is directed to a coating having a higher heat resistance thanthe cover material to prevent shallowing of dimples or dulling of dimpleedges upon the coating application.

In addition, various golf ball compositions with purported improvedlight stability and durability have been disclosed. For example, U.S.Pat. No. 6,458,307 is directed to thermoplastic cover materials with areported improvement in light stability, cut resistance, and abrasionresistance. U.S. Pat. No. 6,369,125 relates to crosslinkablethermoplastic compositions that can be melted and reformed and also haveimproved scuff and cut resistance over conventional balata covers.

While the efforts described above compensate for many problemsassociated with golf play during non-optimal conditions, no method ofmaterial has addressed all of the problems at once. In addition, most ofthe methods used to compensate for extreme temperature conditionsinvolve the use of a special indicator, club, or warmer. Therefore,there remains a continuing need for novel compositions that solvetemperature-related problems of conventionally-formed golf balls andgolf clubs, e.g., resiliency and material degradation at non-optimaltemperatures. In particular, it would be advantageous to provide acomposition using trifunctional materials that provides heat resistanceand dimensional stability, as well as improved resiliency, to golf balland club components formed therefrom at non-optimal temperatures.

SUMMARY OF THE INVENTION

The present invention is directed to a golf ball including at least onelayer formed from a composition including at least one trifunctionalcomponent selected from the group consisting of a trifunctionalisocyanate, a trifunctional amine-terminated component, or atrifunctional curing agent, wherein the coefficient of restitutionchanges by about 5 percent or less with a corresponding temperaturedecrease of 15° F. or more. In one embodiment, the coefficient ofrestitution changes by about 3 percent or less with a correspondingtemperature decrease of about 45° F. or more. In another embodiment, thecoefficient of restitution has no appreciable change with acorresponding temperature decrease of about 60° F. or more.

The golf ball may include a core and a cover, preferably having a coverformed of the composition. In one embodiment, the cover includes atleast two layers. Furthermore, the trifunctional component may beselected from the group consisting of an isocyanurate trimer ofhexamethylene diisocyanate, an isocyanurate trimer of toluenediisocyanate, an isocyanurate trimer of isophorone diisocyanate, a blendof isophorone diisocyanate and an isocyanurate trimer of isophoronediisocyanate, and mixtures thereof. Moreover, the trifunctional curingagent may be selected from the group consisting of propylene-oxide basedtriamine, ethylene oxide triamine, diethylene triamine,trimethylolpropane-based triamine, glycerin-based triamine,N-(2-aminoethyl)-1,3-propylenediamine, and mixtures thereof. Inaddition, the composition may be thermoset.

The present invention is also directed to a golf ball component formedfrom a composition including at least one trifunctional componentselected from the group consisting of a trifunctional isocyanate, atrifunctional amine-terminated component, or a trifunctional curingagent, wherein the component has a COR profile that exhibits an increaseas temperature decreases from about 70° F. to about 20° F. In oneembodiment, the COR of the golf ball increases by about 7 percent ormore with a corresponding temperature decrease of about 15° F. orgreater. In another embodiment, the COR of the golf ball increases byabout 15 percent or more with a corresponding temperature decrease ofabout 30° F. or greater. In still another embodiment of the invention,the tan δ of the component decreases by about 40 percent or greater whenthe temperature decreases by about 20° F. or more.

In this aspect of the invention, the trifunctional component may beselected from the group consisting of an isocyanurate trimer ofhexamethylene diisocyanate, an isocyanurate trimer of toluenediisocyanate, an isocyanurate trimer of isophorone diisocyanate, a blendof isophorone diisocyanate and an isocyanurate trimer of isophoronediisocyanate, and mixtures thereof.

The invention further relates to a chemical composition for golf ballsincluding a polyurea prepolymer, which includes an isocyanate and anamine-terminated compound, and a curing agent, wherein at least one ofthe isocyanate, amine-terminated compound, or curing agent includesthree functional groups. The composition may include at least one of atrifunctional isocyanate, a trifunctional polyol, a trifunctionalamine-terminated component, a trifunctional hydroxy-terminated curingagent, a trifunctional amine-terminated curing agent, a trifunctionalisocyanurate, or combinations thereof. In one embodiment, thecomposition includes an isocyanurate trimer of an isocyanate.

In one embodiment, the composition has a COR profile that exhibits anincrease as temperature decreases from about 70° F. to about 20° F. Inanother embodiment, the composition has a tan δ profile that exhibits adecrease as temperature decreases from about 70° F. to about 20° F.

In this aspect of the invention, the composition may consist of linkageshaving the general formula:

wherein x is the chain length, wherein R₁ includes a straight chain orbranched hydrocarbon chain having about 1 to about 20 carbons, apolyether chain, a polyester chain, a polycaprolactone chain, orpolycarbonate chain, and wherein R includes aliphatic, aromatic, oraraaliphatic hydrocarbons.

The invention also relates to a chemical composition for golf ballsincluding a polyurethane prepolymer, which includes an isocyanate and apolyol, and a curing agent, wherein at least one of the isocyanate,polyol, or curing agent includes three functional groups. In oneembodiment, the composition includes at least one trifunctionalcomponent selected from the group consisting of a trifunctionalisocyanate, a trifunctional polyol, a trifunctional amine-terminatedcomponent, a trifunctional hydroxy-terminated curing agent, atrifunctional amine-terminated curing agent, a trifunctionalisocyanurate, and combinations thereof. The isocyanate may be selectedfrom the group consisting of an isocyanurate trimer of hexamethylenediisocyanate, an isocyanurate trimer of toluene diisocyanate, anisocyanurate trimer of isophorone diisocyanate, a blend of isophoronediisocyanate and an isocyanurate trimer of isophorone diisocyanate, andmixtures thereof.

The polyol may have the following structure:

wherein R is polyether-based, polyester-based, polycaprolactone-based,or polycarbonate-based, and wherein n is 1 or greater. In oneembodiment, the polyol includes a low equivalent weight liquidpolycaprolactone triol. In another embodiment, the curing agent includeshydroxyl functional groups, amine functional groups, or combinationsthereof. In yet another embodiment, the curing agent has threefunctional groups. The curing agent may be selected from the groupconsisting of propylene-oxide based triamine, ethylene oxide triamine,diethylene triamine, trimethylolpropane-based triamine, glycerin-basedtriamine, N-(2-aminoethyl)-1,3-propylenediamine, and mixtures thereof.

In this aspect of the invention, the composition preferably has at leastone of a COR profile that exhibits an increase as temperature decreasesfrom about 70° F. to about 20° F., a tan δ profile that exhibits adecrease as temperature decreases from about 70° F. to about 20° F.

The invention is further directed to a golf ball including a core and acover, wherein at least one layer includes a composition including atleast one trifunctional material, wherein the composition has acrosslink density of about 0.2 or greater, preferably about 0.5 orgreater, more preferably about 0.8 or greater. In one embodiment, the atleast one trifunctional material is selected from the group consistingof a trifunctional isocyanate, a trifunctional polyol, a trifunctionalamine-terminated component, a trifunctional hydroxy-terminated curingagent, a trifunctional amine-terminated curing agent, a trifunctionalisocyanurate, and combinations thereof.

In this aspect of the invention, the composition may include at leastone polyurea prepolymer and at least one curing agent. In oneembodiment, the polyurea prepolymer includes the at least onetrifunctional material. In another embodiment, the curing agent includesthe at least one trifunctional material. Alternatively, the compositionmay include at least one polyurethane prepolymer and at least one curingagent.

The present invention further relates to a golf ball including a core,an inner cover layer, and an outer cover layer, wherein the outer coverlayer is formed of a composition including a polyurea prepolymer, whichis formed from the reaction product of an isocyanate and anamine-terminated compound, and a curing agent, wherein at least one ofthe isocyanate, amine-terminated compound, or curing agent has threefunctional groups, and wherein the composition has a crosslink densityof about 0.2 or greater, preferably about 0.5 or greater, and morepreferably about 0.8 or greater.

In one embodiment, the composition includes linkages having the generalformula:

wherein x is the chain length, wherein R₁ includes a straight chain orbranched hydrocarbon chain having about 1 to about 20 carbons, apolyether chain, a polyester chain, a polycaprolactone chain, orpolycarbonate chain, and wherein R includes aliphatic, aromatic, oraraaliphatic hydrocarbons. In another embodiment, the compositionincludes only linkages having the general formula:

wherein x is the chain length, wherein R₁ includes a straight chain orbranched hydrocarbon chain having about 1 to about 20 carbons, apolyether chain, a polyester chain, a polycaprolactone chain, orpolycarbonate chain, and wherein R includes aliphatic, aromatic, oraraaliphatic hydrocarbons.

The composition may include at least one of a trifunctional isocyanate,a trifunctional polyol, a trifunctional amine-terminated component, atrifunctional hydroxy-terminated curing agent, a trifunctionalamine-terminated curing agent, a trifunctional isocyanurate, orcombinations thereof.

The invention is also directed to a chemical composition for golf ballsincluding a polyurethane prepolymer, which is formed from the reactionproduct of an isocyanate and a polyol, and a curing agent, wherein atleast one of the isocyanate, polyol, or curing agent includes threefunctional groups, and wherein the composition has an average molecularweight between crosslinks of about 3000 or greater, preferably about4000 or greater.

In this aspect of the invention, the composition may include at leastone trifunctional component selected from the group consisting of atrifunctional isocyanate, a trifunctional polyol, a trifunctionalamine-terminated component, a trifunctional hydroxy-terminated curingagent, a trifunctional amine-terminated curing agent, a trifunctionalisocyanurate, and combinations thereof.

In one embodiment, the isocyanate is selected from the group consistingof an isocyanurate trimer of hexamethylene diisocyanate, an isocyanuratetrimer of toluene diisocyanate, an isocyanurate trimer of isophoronediisocyanate, a blend of isophorone diisocyanate and an isocyanuratetrimer of isophorone diisocyanate, and mixtures thereof.

In another embodiment, the composition has at least one of a COR profilethat exhibits an increase as temperature decreases from about 70° F. toabout 20° F., a tan δ profile that exhibits a decrease as temperaturedecreases from about 70° F. to about 20° F., or both.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention can be ascertained fromthe following detailed description that is provided in connection withthe drawing(s) described below:

FIG. 1 is a cross-sectional view of a two layer ball, wherein at least aportion of the golf ball is formed from the compositions of theinvention;

FIG. 2 is a cross-sectional view of a multi-component golf ball, whereinat least a portion of the golf ball is formed from the compositions ofthe invention;

FIG. 3 is a cross-sectional view of a multi-component golf ballincluding a large core, an intermediate layer, and a thin outer coverlayer disposed thereon, wherein at least a portion of the golf ball isformed from the compositions of the invention;

FIG. 4 is a cross-sectional view of a multi-component golf ballincluding a core, an outer core layer, a thin inner cover layer, and athin outer cover layer disposed thereon, wherein at least a portion ofthe golf ball is formed from the compositions of the invention;

FIGS. 5-6 are graphical representations of the coefficient ofrestitution in response to temperature changes for a unitary ball moldedfrom a composition of the present invention and a golf ball having acore, inner layer, and cover made according to the invention; and

FIGS. 7-8 are graphical representations of the tangent delta-temperaturerelationship for compositions made according to the invention and acomparison composition.

DETAILED DESCRIPTION OF THE INVENTION

The present invention contemplates compositions for golf balls and golfclubs that overcome temperature-related problems associated with balland club components formed from known compositions. In particular, thecompositions of the invention are formed using at least onetrifunctional material that increases the crosslinking density of theelastomer, which, in turn, improves the heat resistance of thecomposition and any golf components formed therefrom. In addition, theuse of at least one trifunctional material in the compositions of theinvention results in improved resiliency of the golf components atnon-optimal temperatures. For the purposes of the present invention,non-optimal temperatures are below about 70° F. and above about 95° F.In one embodiment, non-optimal temperatures are those temperaturesoutside of the about 59° F. to about 95° F. range.

For example, the compositions of the invention may be polyurethane-and/or polyurea-based, formed with a trifunctional diisocyanate, polyol,and/or amine. In particular, the compositions of the invention mayinclude at least one of a trifunctional diisocyanate, a trifunctionalpolyol, a trifunctional amine-terminated component, a trifunctionalhydroxy-terminated curing agent, a trifunctional amine-terminated curingagent, a trifunctional isocyanurate, or combinations thereof.

The compositions of the invention may be aromatic, aromatic-aliphatic,or aliphatic, which provide varying degrees of light stability. Along acontinuum, an aromatic composition is less light stable than anaromatic-aliphatic composition, which is less light stable than analiphatic composition. For example, an aliphatic composition madeaccording to the invention includes only saturated components, i.e.,components substantially free of unsaturated carbon-carbon bonds oraromatic groups, which prevent yellowing over time. The term“saturated,” as used herein, refers to compositions having saturatedaliphatic and alicyclic polymer backbones, i.e., with no carbon-carbondouble bonds. Aromatic-aliphatic compositions according to the inventionmay include both saturated and unsaturated components, whereas aromaticcompositions include only unsaturated components. It is important tonote, however, that aromatic compositions made according to theinvention may include light stabilizers to improve light stability.Thus, light stability may be accomplished in a variety of ways for thepurposes of this application.

Furthermore, the compositions of the invention may be used in a varietyof golf ball constructions, e.g., one-piece, two-piece, or multilayerballs, as well as golf club components, e.g., club head inserts. Whenused to form various golf ball components, e.g., golf ball covers, thecompositions of the invention produce golf balls with improved physicaland aerodynamic properties as compared to golf balls incorporatingconventional materials when played in non-optimal temperatureconditions. Furthermore, when the compositions of the invention areformed using saturated components, the light stability of suchcompositions (and golf components formed therefrom) is improved overthose compositions formed with traditional aromatic castablecompositions.

Compositions of the Invention

As briefly mentioned above, the compositions of the invention include atleast one trifunctional material to improve the crosslink density of thecompositions and components formed therefrom. The increased crosslinkdensity provides a composition with greater dimensional stability,higher mechanical strength, and improved heat resistance.

In addition to improved heat resistance and dimensional stability, thecompositions of the invention have improved resiliency at non-optimaltemperatures, i.e., temperatures below about 70° F. and greater thanabout 95° F. As such, the compositions of the invention preferably havea glass transition temperature (T_(g)) lower than conventional golfcomponent compositions. The specific nature of this improvement will bediscussed in greater detail below, however, without being bound by anyparticular theory, a higher molecular weight between crosslinks isbelieved to lead to a lower glass transition temperature because of theincreased flexibility in the individual polymer chains.

As used herein, the glass transition temperature refers to thetemperature at which, when cooling a polymer from a molten state, themechanical properties of the polymer change from those of a rubber(elastic) to those of a glass (brittle). Rubber elastomers likepolyisoprene and polyisobutylene, are used above their T_(g)'s, i.e., inthe rubbery state, where they are soft and flexible. As such, a golfball component formed from these rubbery elastomers will have a hardfeel and lose resiliency as the temperature approaches the T_(g).Therefore, in one aspect of the invention, the compositions of theinvention have a T_(g) that is at least about 5 percent lower than aconventional composition that does not include a trifunctional material.In another embodiment, the T_(g) is at least about 8 percent lower,preferably at least about 10 percent lower than the T_(g) of acomposition that does not include a trifunctional material.

According to one aspect of the present invention, the compositions ofthe invention, which include at least one trifunctional material, arebased on polyurethane and/or polyurea linkages. The polyurethane linkagemay be formed with at least one isocyanate and at least one polyol,whereas the polyurea linkage is formed from at least one isocyanate andat least one amine-terminated curing agent. The linkages are cured withat least one curing agent, preferably a hydroxy-terminated curing agentand/or an amine-terminated curing agent. Thus, at least one of theisocyanate, polyol, amine-terminated compound, or curing agent istrifunctional.

Trifunctional Materials

Any trifunctional material is contemplated for incorporation into thecompositions of the invention. As used herein, a “trifunctionalmaterial” refers to a material that has the theoretical functionality ofthree (f=3). Because functionality refers to the number of reactivegroups attached to the molecule, a trifunctional material according tothe invention has three reactive groups.

By way of example, the functionality on a polyol is the hydroxyl (OH)group, which usually ranges from about two, to more than about six.Theoretically, a trifunctional polyol has three reactive hydroxyl groupsand, thus, a functionality of three (f=3), however, not every moleculecontains the maximum of reactive groups it theoretically could have. Asan example, the trifunctional polyol contains some amount ofdifunctional (f=2) molecules and monofunctional (f=1) molecules.Therefore, the actual functionality of a trifunctional materialaccording to the present invention may be less than three. The presentinvention contemplates materials having a theoretical functionality ofthree, as well as those materials having an actual functionality of lessthan three.

In one embodiment, the trifunctional material according to the presentinvention may be at least one of a trifunctional isocyanate, atrifunctional polyol, a trifunctional amine-terminated component, atrifunctional hydroxy-terminated curing agent, a trifunctionalamine-terminated curing agent, a trifunctional isocyanurate, andcombinations thereof.

A trifunctional isocyanate according to the present invention may berepresented by the following generic structure:

where R may be cyclic, aromatic, aliphatic, linear, branched,isocyanurate, biuret, triisocyanate, or substituted hydrocarbon moietyincluding from about 1 to about 20 carbon atoms, e.g., arylenes,araalkylenes, or cycloalkylenes. When multiple cyclic or aromatic groupsare present, linear, branched, or substituted hydrocarbon groupscontaining from about 1 to about 10 carbon atoms may be present asspacers between such cyclic or aromatic groups. In some cases, thecyclic or aromatic groups may be substituted at the 2-(ortho), 3-(meta),and/or 4-(para) positions. Substituted groups may include, but are notlimited to, halogens, cyano groups, amine groups, silyl groups, hydroxylgroups, acid groups, alkoxy groups, primary or secondary or tertiaryhydrocarbon groups, or a combination of two or more groups thereof.

Commercially-available trifunctional isocyanates and isocyanuratetrimers of any isocyanate include, but are not limited to, DESDOMUR®N-3300 (isocyanurate trimer of hexamethylene diisocyanate) and DESDOMUR®IL (isocyanurate trimer of toluene diisocyanate), both manufactured byBayer Corporation, and VESTANAT® T 1890 (isocyanurate trimer ofisophorone diisocyanate) and VESTANAT® T 6040 (blend of isophoronediisocyanate and isocyanurate trimer of isophorone diisocyanate), bothmanufactured by Degussa Corporation. In addition, biurets ofhexamethylene diisocyanate are contemplated for use with the presentinvention.

A trifunctional polyol may be represented by the following genericstructure:

where R may be polyether-based, polyester-based, polycaprolactone-based,or polycarbonate-based and where n is the chain length, i.e., 1 orgreater. For example, a suitable trifunctional polyol for use with thepresent invention is a low equivalent weight liquid polycaprolactonetriol, which is commercially available as TONE® POLYOL 305 from DowChemical Company.

A trifunctional amine-terminated component may include those compoundshaving the following generic structures:

where n is the chain length, i.e., 1 or greater, R may behydrocarbon-based, polyether-based, polyester-based,polycaprolactone-based, polycarbonate-based, polyamide-based, and R₁ maybe any branched or linear alkyl group having from about 1 to about 20carbon atoms, preferably about 1 to about 12 carbon atoms, a phenylgroup, a cyclic group, a isopropyl group, a propane nitrile group, ormixture thereof.

For example, the trifunctional amine-terminated component may be apropylene-oxide based triamine. An example of a propylene-oxide basedtriamine is polyoxypropylene triamine, which is commercially availableunder the tradename JEFFAMINE® (JEFFAMINE® T-403, T-5000, XTJ-509,manufactured by Huntsman). In addition, ethylene oxide triamine,diethylene triamine, trimethylolpropane-based triamine, glycerin-basedtriamine, and N-(2-aminoethyl)-1,3-propylenediamine are suitable for usewith the present invention.

A trifunctional hydroxy-terminated curing agent for use with the presentinvention may include compounds having the structures provided abovewith respect to polyols. In particular, suitable trifunctionalhydroxy-terminated curing agents include, but are not limited to,trimethylolpropane (TMP), trimethylolethane, 1,2,4-butanetriol,1,2,6-hexanetriol, triethanolamine, triisopropanolamine, and mixturesthereof.

A trifunctional amine-terminated curing agent may include any of thestructures provided above with respect to the amine-terminatedcomponents. For example, suitable trifunctional amine-terminated curingagents include, but are not limited to, ethylene oxide and propyleneoxide-based triamines, diethylene triamine, dipropylene triamine,trimethylolpropane-based triamines, glycerin-based triamines,N-(2-aminoethyl)-1,3-propylenediamine, and mixtures thereof.

In addition to the above-referenced trifunctional materials, othersuitable materials may increase the crosslink density of thecompositions of the invention. For example, some low molecular weightprimary diamines may be employed to increase the crosslink density ofthe compositions of the invention. Suitable primary diamines for usewith the present invention include, but are not limited to,4,4′-diaminodicyclohexylmethane,3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, polyoxyethylene diamines,polyoxypropylene diamines, (ethylene oxide-capped)-polyoxypropylenediamines, polytetramethylene ether diamines, and mixtures thereof.

Polyurethane Prepolymers

The compositions of the invention may include a polyurethane linkage,where the linkage is a product formed by a reaction between at least oneisocyanate and at least one polyol. Specifically, an isocyanate groupreacts with the hydroxyl groups of a polyol to form a repeating urethanelinkage, which has the following general structure:

where x is the chain length, i.e., about 1 or greater, where R₁ is astraight chain or branched hydrocarbon chain, polyether chain, polyesterchain, polycaprolactone chain, or polycarbonate chain having about 1 toabout 20 carbons, and where R can be aliphatic, aromatic, oraraaliphatic hydrocarbons.

In one embodiment, the composition of the invention includes at leastone polyurethane prepolymer, which is the reaction product of at leastone isocyanate and at least one polyol, cured with at least one curingagent, wherein any one of the components may be a trifunctionalmaterial. In another embodiment, the composition of the inventionincludes at least one trifunctional material in addition to the at leastone isocyanate, at least one polyol, and at least one curing agent,wherein the at least one isocyanate, at least one polyol, and at leastone curing agent may or may not be trifunctional materials.

Thus, any of the trifunctional materials discussed above, e.g., thetrifunctional isocyanates, biurets, and isocyanurates, trifunctionalpolyols, trifunctional amine-terminated components, trifunctionalhydroxy-terminated curing agents, and trifunctional amine-terminatedcuring agents are contemplated for use in preparing compositions thatinclude a polyurethane linkage according to the present invention.

The polyurethane compositions may be aliphatic (saturated) and,therefore, in one embodiment, the prepolymer is the product of areaction between at least one saturated isocyanate and at least onesaturated polyol. In another embodiment, at least one of the saturatedcomponents is a trifunctional material according to the presentinvention.

Isocyanates for use with the polyurethane prepolymer include straight orbranched aliphatic (saturated) chains, cycloaliphatic, aromaticaliphatic, derivatives thereof, and combinations of these compoundshaving two or more isocyanate (NCO) groups per molecule. As used herein,aromatic aliphatic compounds should be understood as those containing anaromatic ring, wherein the isocyanate group is not directly bonded tothe ring. One example of an aromatic aliphatic compound is atetramethylene diisocyanate (TMXDI). As mentioned above, however, theisocyanate is preferably saturated to improve the light stability of thecomposition of the invention. The isocyanates may be organicpolyisocyanate-terminated prepolymers, low free isocyanate prepolymers(discussed in more detail below), and mixtures thereof. Theisocyanate-containing reactable component may also include anyisocyanate-functional monomer, dimer, trimer, or multimeric adductthereof, prepolymer, quasi-prepolymer, or mixtures thereof.Isocyanate-functional compounds may include monoisocyanates orpolyisocyanates that include any isocyanate functionality of two ormore.

In one embodiment, the isocyanate is any straight or branched aliphatic,cycloaliphatic, or aromatic aliphatic material having three functional(NCO) groups per molecule. For example, the isocyanate may be anisocyanurate trimer of any isocyanate. When used in the polyurethaneprepolymers of the invention, an isocyanurate trimer of an isocyanate ispreferably included in an amount of about one percent to about 15percent by weight of the total prepolymer. In one embodiment, theisocyanurate trimer of an isocyanate is present in an amount of about 2percent to about 13 percent by weight of the total prepolymer,preferably about 3 percent to about 12 percent by weight of the totalprepolymer. In another embodiment, the prepolymer includes about 4percent to about 10 percent of an isocyanurate trimer of an isocyanate.

Thus, in addition to the trifunctional isocyanates discussed earlier,suitable isocyanate-containing components include isocyanates having thegeneric structure: O═C═N—R—N═C═O, where R is a cyclic, aromatic,aliphatic, linear, branched, or substituted hydrocarbon moietycontaining from about 1 to 20 carbon atoms, such as arylenes,aralkylenes, alkylenes, or cycloalkylenes. When multiple cyclic oraromatic groups are present, linear, branched, or substitutedhydrocarbons containing from about 1 to 10 carbon atoms can be presentas spacers between the cyclic or aromatic groups. In some cases, thecyclic or aromatic group(s) may be substituted at the 2-, 3-, and/or 4-positions, respectively. Substituted groups may include, but are notlimited to, halogens, cyano groups, amine groups, silyl groups, hydroxylgroups, acid groups, alkoxy groups, primary, secondary, or tertiaryhydrocarbon groups, or a mixture thereof.

Examples of saturated (aliphatic) isocyanates that can be used in thepolyurethane prepolymer include, but are not limited to, ethylenediisocyanate; propylene-1,2-diisocyanate; tetramethylene diisocyanate;1,4-tetramethylene diisocyanate; 1,5-pentamethylene diisocyanate;2-methyl-1,5-pentamethylene diisocyanate; 1,6-hexamethylene diisocyanate(HDI); HDI biuret prepared from HDI; octamethylene diisocyanate;decamethylene diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate;2,4,4-trimethylhexamethylene diisocyanate; 1,7-heptamethylenediisocyanate; 1,8-octamethylene diisocyanate; 1,9-novamethylenediisocyanate; 1,10-decamethylene diisocyanate; 1,12-dodecanediisocyanate; 1,3-cyclobutane diisocyanate; 1,2-cyclohexanediisocyanate; 1,3-cyclohexane diisocyanate; 1,4-cyclohexanediisocyanate; methylcyclohexylene diisocyanate (HTDI);2,4-methylcyclohexane diisocyanate; 2,6-methylcyclohexane diisocyanate;4,4′-dicyclohexane diisocyanate; 2,4′-dicyclohexane diisocyanate;1,3,5-cyclohexane triisocyanate; isocyanatomethylcyclohexane isocyanate;1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane;isocyanatoethylcyclohexane isocyanate; bis(isocyanatomethyl)-cyclohexanediisocyanate; 4,4′-bis(isocyanatomethyl) dicyclohexane;2,4′-bis(isocyanatomethyl) dicyclohexane; isophorone diisocyanate(IPDI); triisocyanate of HDI; triisocyanate of2,2,4-trimethyl-1,6-hexane diisocyanate (TMDI); 4,4′-dicyclohexylmethanediisocyanate (H₁₂MDI); 2,4-hexahydrotoluene diisocyanate;2,6-hexahydrotoluene diisocyanate; aromatic aliphatic isocyanate, suchas 1,2-, 1,3-, and 1,4-xylene diisocyanate; meta-tetramethylxylenediisocyanate (m-TMXDI); para-tetramethylxylene diisocyanate (p-TMXDI);saturated trimerized isocyanurates, such as isocyanurates ofhexamethylene diisocyanate, isocyanurates of isophorone diisocyanate,HDI biurets prepared from HDI, isocyanurates of trimethyl-hexamethylenediisocyanate, and mixtures thereof; uretdione of hexamethylenediisocyanate, and mixtures thereof; modified polyisocyanate derived fromthe above isocyanates and polyisocyanates; and mixtures thereof.

In one embodiment, the saturated isocyanates include isophoronediisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (H₁₂MDI),1,6-hexamethylene diisocyanate (HDI), or a combination thereof.

As briefly discussed, aromatic aliphatic isocyanates may also be used toform the polyurethane prepolymer. While use of aromatic aliphaticmaterials does not confer the same amount of light stability to theresultant product compared to those including purely aliphaticmaterials, it does provide a greater degree of light stability to theresultant product compared to those formed with purely aromaticmaterials. Examples of aromatic aliphatic isocyanates include 1,2-,1,3-, and 1,4-xylene diisocyanate; 1,2-, 1,3-, and1,4-bis-(sec-butylamino) xylene; meta-tetramethylxylene diisocyanate(m-TMXDI); para-tetramethylxylene diisocyanate (p-TMXDI); a modifiedpolyisocyanate derived from the above isocyanates and polyisocyanates;and mixtures thereof. In addition, the aromatic aliphatic isocyanatesmay be mixed with any of the saturated isocyanates listed above for thepurposes of this invention.

Unsaturated isocyanates, i.e., aromatic compounds, may also be used withthe present invention, although the use of unsaturated compounds in theprepolymer is preferably coupled with the use of a light stabilizer orpigment as discussed below. Examples of unsaturated diisocyanatesinclude, but are not limited to, substituted and isomeric mixturesincluding 2,2′-, 2,4′-, and 4,4′-diphenylmethane diisocyanate (MDI);2,2′-, 2,4′-, and 4,4′-biphenylene diisocyanate;3,3′-dimethyl-4,4′-biphenyl diisocyanate (TODI);3,3′-dimethyl-4,4′-diphenylmethane diisocyanate; toluene diisocyanate(TDI); polymeric MDI (PMDI, a brown liquid composed of approximately 50%methylene diisocyanate with the remainder comprised of oligomers ofMDI); carbodimide-modified liquid 4,4′-diphenylmethane diisocyanate;para-phenylene diisocyanate (PPDI); meta-phenylene diisocyanate (MPDI);ortho-phenylene diisocyanate; 4-chloro-1,3-phenylene diisocyanate;triphenylmethane-4,4′-, and triphenylmethane-4,4″-triisocyanate;1,5-naphthalene diisocyanate (NDI); 1,5-tetrahydronaphthalenediisocyanate; anthracene diisocyanate; tetracene diisocyanate; dimerizeduretdiones of any diisocyanate or polyisocyanate, such as uretdione oftoluene diisocyanate, uretdione of diphenylmethane diisocyanate, andmixtures thereof; unsaturated trimerized isocyanurates, such as trimersof diphenylmethane diisocyanate, trimers of tetramethylxylenediisocyanate, isocyanurates of toluene diisocyanate, and mixturesthereof; monomeric trisocyanates such as 2,4,4′-diphenylenetriisocyanate, 2,4,4′-diphenylmethane triisocyanate,4,4′,4″-triphenylmethane triisocyanate, and mixtures thereof; andmixtures thereof.

Suitable polyols for use in the polyurethane prepolymer may be linear orbranched organic, modified organic, saturated, aliphatic, alicyclic,unsaturated, araliphatic, aromatic, substituted, or unsubstitutedcompounds. The polyol preferably has two or more reactive hydroxy groupsper molecule, such as primary or secondary hydroxyl groups, and at leastone cyclic, aromatic, aliphatic, linear, branched, or substitutedhydrocarbon moiety containing from 1 to about 20 carbon atoms, such asarylenes, aralkylenes, alkylenes, or cycloalkylenes. When the polyol isa trifunctional material, it has three reactive hydrogen groups permolecule. Any of the trifunctional polyols discussed earlier aresuitable for use in this context.

When multiple cyclic or aromatic groups are present, linear, branched orsubstituted hydrocarbons containing from 1 to about 10 carbon atoms canbe present as spacers between such cyclic or aromatic groups. In somecases, the cyclic or aromatic group(s) may be substituted at the2-(ortho-), 3-(meta-), and/or 4-(para-) positions. Substituted groupsmay include, but are not limited to, halogens, cyano groups, aminegroups, silyl groups, hydroxyl groups, acid groups, alkoxy groups,primary, secondary, or tertiary hydrocarbon groups, dimerate alcohols,or a combination of two or more groups thereof. Any and all of thepolyols disclosed herein may be used alone or in combination of two ormore thereof.

Thus, polyols for use with the present invention include, but are notlimited to, hydroxy-terminated polyethers, hydroxy-terminatedpolyesters, hydroxy-terminated polycaprolactones, hydroxy-terminatedpolycarbonates, hydroxy-terminated polyhydrocarbons, hydroxy-terminatedacid functional oligomers or polymers (or ionomers thereof derived frompartial or full neutralization with organic or inorganic cations), andthe like. The polyols for use with the present invention preferably havea molecular weight of about 200 or greater.

Examples of hydroxy-terminated polyethers include, but are not limitedto polytetramethylene ether glycol (“PTMEG”); low-molecular-weightPTMEG; modified PTMEG; hydroxy-terminated copolymer ofpolytetrahydrofuran and polymethyltetrahydrofuran (“PTG-L”);poly(oxyethylene)glycol; poly(oxypropylene)glycol; (ethyleneoxide)-capped poly(oxypropylene) ether glycol;poly(oxyethylene-co-oxypropylene) glycol; and mixtures thereof.

Suitable hydroxy-terminated polyesters include, but are not limited to,poly(ethylene adipate) glycol; poly(butylene adipate) glycol;poly(hexamethylene adipate) glycol; poly(ethylene propylene adipate)glycol; poly(ethylene butylene adipate) glycol; poly(hexamethylenebutylene adipate) glycol; (o-phthalate-1,6-hexanediol)-based polyesterpolyol; poly(ethylene terephthalate)-based polyester polyol, andmixtures thereof.

Suitable hydroxy-terminated polycaprolactones include, but are notlimited to, (alkylene oxide)-initiated polycaprolactones; (ethyleneglycol)-initiated polycaprolactone; (diethylene glycol)-initiatedpolycaprolactone; (propylene glycol)-initiated polycaprolactone;(dipropylene glycol)-initiated polycaprolactone;1,4-butanediol-initiated polycaprolactone; trimethylolpropane-initiatedpolycaprolactone; (neopentyl glycol)-initiated polycaprolactone;1,6-hexanediol-initiated polycaprolactone; PTMEG-initiatedpolycaprolactone; 2-ethyl-2-(hydroxymethyl)-1,3-propanediol initiatedpolycaprolactone; and mixtures thereof.

Examples of suitable hydroxy-terminated polycarbonates include, but arenot limited to poly(phthalate carbonate) glycol; poly(hexamethylenecarbonate) glycol; poly(1,4-cyclohexanedimethylene carbonate) glycol;(bisphenol A)-based polycarbonate glycols; and mixtures thereof.

Non limiting examples of hydroxy-terminated polyhydrocarbons includepolyisoprene polyol (a.k.a. liquid isoprene rubber); poly(hydrogenatedisoprene) polyol; polybutadiene polyol; poly(hydrogenated butadiene)polyol; and mixtures thereof.

Hydroxy-terminated acid functional oligomers or polymers that may beused with the present invention include, but are not limited to, theacid functional polyols as disclosed in U.S. Pat. No. 6,207,784, whichis incorporated in its entirety by reference herein. Otherhydroxy-terminated polyols may be used with the present invention, suchas hydroxy-terminated polyolefins; hydroxy-terminated polyamides;glycerol-based polyols; (castor oil)-based polyols; hydroxy-terminatedalkylene-styrene copolymers (a.k.a. Kraton® polyols); andhydroxy-terminated acrylic polyols.

Saturated members of the above-listed hydroxy-terminated polyols arepreferred for use in the present invention, because they afford superiorlight stability when incorporated into the golf ball compositions of theinvention. Saturated hydroxy-terminated polyols may be aliphatic,alicyclic, or fully hydrogenated. Exemplary saturated hydroxy-terminatedpolyols include, but are not limited to, PTMEG; low-molecular-weightPTMEG; modified PTMEG; PTG-L; poly(oxyethylene)glycol;poly(oxypropylene)glycol; (ethylene oxide)-capped poly(oxypropylene)ether glycol; poly(ethylene adipate) glycol; poly(butylene adipate)glycol; poly(hexamethylene adipate) glycol; poly(ethylene propyleneadipate) glycol; poly(ethylene butylene adipate) glycol;poly(hexamethylene butylene adipate) glycol; (alkylene oxide)-initiatedpolycaprolactones; (ethylene glycol)-initiated polycaprolactone;(diethylene glycol)-initiated polycaprolactone; (propyleneglycol)-initiated polycaprolactone; (dipropylene glycol)-initiatedpolycaprolactone; 1,4-butanediol-initiated polycaprolactone;trimethylolpropane-initiated polycaprolactone; (neopentylglycol)-initiated polycaprolactone; 1,6-hexanediol-initiatedpolycaprolactone; PTMEG-initiated polycaprolactone; poly(hexamethylenecarbonate) glycol; saturated poly(hydrogenated isoprene) polyol;saturated poly(hydrogenated butadiene) polyol; saturated dimerate ortrimerate polyols of fatty acids or isostearic acid; saturatedhydroxy-terminated polyolefins; saturated hydroxy-terminated polyamides;saturated glycerol-based polyols; saturated (castor oil)-based polyols;and saturated hydroxy-terminated alkylene-styrene copolymers. In oneembodiment, the saturated polyol has three reactive hydrogen groups permolecule.

In another aspect of the present invention, the polyol is based on ahydrophobic backbone. By using polyols based on a hydrophobic backbone,the polyurethane prepolymers of the invention may be more waterresistant than those polyurethane prepolymers having polyols without ahydrophobic backbone. Some non-limiting examples of polyols based on ahydrophobic backbone include hydrocarbon polyols, hydroxy-terminatedpolybutadiene polyols, polyethers, polycaprolactones, and polyesters. Inone embodiment, the polyol based on a hydrophobic backbone has threereactive hydrogen groups per molecule.

The isocyanates suitable for use with the present invention may have anyamount of NCO. As used herein, “percent NCO” refers to the percent byweight of free, reactive, and unreacted isocyanate functional groups inan isocyanate-functional molecule or material. The percent NCO iscalculated as follows: the total atomic weight of all the NCO groups inthe molecule or material is divided by its total molecular weight andmultiplied by 100.

When formed, polyurethane prepolymers preferably contain about 10percent to about 25 percent by weight of the prepolymer of freeisocyanate monomer (unreacted NCO groups), preferably about 10 percentto about 20 percent by weight. The number of unreacted NCO groups in thepolyurethane prepolymer may be varied to control such factors as thespeed of the reaction, the resultant hardness of the composition, andthe like. For example, as the weight percent of unreacted isocyanategroups increases, the hardness also increases in a somewhat linearfashion.

In another embodiment, the percent of unreacted NCO groups in thepolyurethane prepolymer of isocyanate and polyol may be less than about14 percent. For example, the polyurethane prepolymer may have from about5 percent to about 11 percent unreacted NCO groups, and even morepreferably, from about 6 to about 9.5 percent unreacted NCO groups. Inone embodiment, the percentage of unreacted NCO groups in the prepolymeris about 3 percent to about 9 percent. Alternatively, the percentage ofunreacted NCO groups may be about 7.5 percent or less, and morepreferably, about 7 percent or less. In another embodiment, theunreacted NCO content in the prepolymer is from about 2.5 percent toabout 7.5 percent, and more preferably from about 4 percent to about 6.5percent.

In an alternative embodiment, the polyurethane prepolymer may bestripped of the free isocyanate monomer, i.e., a low free isocyanatemonomer. For example, after stripping, the prepolymer may contain about1 percent or less free isocyanate monomer. In another embodiment, theprepolymer contains about 0.5 percent by weight or less of freeisocyanate monomer.

Polyurea Prepolymers

The compositions of the invention may also be based on a polyurealinkages, where the prepolymer is a product formed by a reaction betweenat least one isocyanate and at least one amine-terminated compound andthen cured with a curing agent. In accordance with the presentinvention, at least one of the polyurea prepolymer components, i.e., theisocyanate or the amine-terminated compound, or the curing agent may bea trifunctional material, i.e., having three functional groups permolecule. In another embodiment, the trifunctional material may beincluded in the polyurea-based composition in addition to the polyureaprepolymer and curing agent. In yet another embodiment, the polyureacomposition may include at least one isocyanate, amine-terminatedcompound, and an amine-terminated curing agent, wherein any or all maybe trifunctional materials, and also include at least one additionaltrifunctional material.

The polyurea compositions may be saturated and, therefore, in oneembodiment, the polyurea composition is the product of a reactionbetween at least one saturated polyurea prepolymer, i.e., at least onesaturated isocyanate and at least one saturated polyamine, which is thencured with at least one saturated amine-terminated curing agent. Atleast one of the saturated components is preferably a trifunctionalmaterial according to the present invention.

For the purposes of the present invention, the polyurea-basedcompositions include primarily urea linkages having the followinggeneral structure:

where x is the chain length, i.e., about 1 or greater, where R₁ is astraight chain or branched hydrocarbon chain, polyether chain, polyesterchain, polycaprolactone chain, or polycarbonate chain having about 1 toabout 20 carbons, and where R can be aliphatic, aromatic, oraraaliphatic hydrocarbons.

The main difference between the polyurethane prepolymers discussed aboveand the polyurea prepolymers discussed in this section is thesubstitution of the polyol component with an amine-terminated compound.Therefore, the isocyanates suitable for inclusion in the polyureaprepolymer are the same as those listed above with respect to thepolyurethane prepolymer, which are incorporated by reference here. And,as above, while saturated isocyanates may be used, aromatic aliphaticisocyanates and aromatic isocyanates are contemplated for use with thepresent invention. In addition, the isocyanate may be a trifunctionalmaterial according to the present invention.

It should be understood, however, that a composition including primarilyurea linkages may have distinctly different properties than acomposition including primarily urethane linkages due to thesubstitution of the polyol with the amine-terminated compound. Forexample, a polyurea prepolymer used according to the present inventionmay provide different shear, cut, resiliency, and adhesion properties tothe resultant elastomer as compared to an elastomer formed with apolyurethane prepolymer.

In addition to the trifunctional amine-terminated compounds discussedearlier, any amine-terminated compound available to one of ordinaryskill in the art is suitable for use in the polyurea prepolymer. Forexample, the amine-terminated compound may include amine-terminatedhydrocarbons, amine-terminated polyethers, amine-terminated polyesters,amine-terminated polycarbonates, amine-terminated polycaprolactones,amine-terminated polyamides, and mixtures thereof. The amine-terminatedcompounds may be in the form of a primary amine (NH₂), a secondary amine(NHR), or mixtures thereof. Co-pending U.S. patent application Ser. No.10/409,144, filed Apr. 9, 2003, entitled “Polyurea and PolyurethaneCompositions for Golf Equipment,” which is incorporated by referenceherein, discloses suitable, but nonlimiting, amine-terminated compoundsfor use with the present invention.

The molecular weight of the amine-terminated compounds for use in theinvention may range from about 100 to about 10,000. As used herein, theterm “about” is used in connection with one or more numbers or numericalranges, and should be understood to refer to all such numbers, includingall numbers in a range. In one embodiment, the amine-terminated compoundis about 500 or greater, preferably about 1000 or greater, and even morepreferably about 2000 or greater. In another embodiment, theamine-terminated compound molecular weight is about 8000 or less,preferably about 4,000 or less, and more preferably about 3,000 or less.For example, in one embodiment, the molecular weight of theamine-terminated compound is about 1000 to about 4000. Because lowermolecular weight polyether amines, which have faster reaction rates, maybe prone to forming solid or gel polyureas, a higher molecular weightoligomer, which has a comparatively slower reaction rate, may be used toavoid solid or gel formation.

In one embodiment, the amine-terminated compound includesamine-terminated hydrocarbons having the following generic structures:

where x is the chain length, i.e., 1 or greater, n is preferably about 1to about 12, and R is any branched or linear alkyl group having fromabout 1 to about 20 carbon atoms, preferably about 1 to about 12 carbonatoms, a phenyl group, a cyclic group, an isopropyl group, a propanenitrile group, or mixture thereof.

The amine-terminated compound may also include amine-terminatedpolyethers having following generic structures:

where x is the chain length, i.e., 1 or greater, n is preferably about 1to about 12, and R is any branched or linear alkyl group having fromabout 1 to about 20 carbon atoms, preferably about 1 to about 12 carbonatoms, a phenyl group, a cyclic group, an isopropyl group, a propanenitrile group, or mixture thereof. One example of an amine-terminatedpolyether is a polyether amine. As used herein, “polyether amine” refersto a polyoxyalkyleneamine containing primary amino groups attached tothe terminus of a polyether backbone. Due to the rapid reaction ofisocyanate and amine, and the insolubility of many urea products,however, the selection of diamines and polyether amines is limited tothose allowing the successful formation of the polyurea prepolymers. Inone embodiment, the polyether backbone is based on tetramethylene,propylene, ethylene, trimethylolpropane, glycerin, and mixtures thereof.

In one embodiment, the polyether amine has the generic structure:

wherein the repeating unit x has a value ranging from about 1 to about70, R is any branched or linear alkyl group having from about 1 to about20 carbon atoms, preferably about 1 to about 12 carbon atoms, a phenylgroup, a cyclic group, an isopropyl group, a propane nitrile group, ormixture thereof, and R₃ is a hydrogen, methyl group, or a mixturethereof. Even more preferably, the repeating unit may be from about 5 toabout 50, and even more preferably is from about 12 to about 35.

In another embodiment, the polyether amine has the generic structure:

wherein the repeating units x and z have combined values from about 3.6to about 8 and the repeating unit y has a value ranging from about 9 toabout 50, R is any branched or linear alkyl group having from about 1 toabout 20 carbon atoms, preferably about 1 to about 12 carbon atoms, aphenyl group, a cyclic group, an isopropyl group, a propane nitrilegroup, or mixture thereof, R₁ is —(CH₂)_(a)—, wherein “a” may be arepeating unit ranging from about 1 to about 10, a phenylene group, acyclic group, or mixtures thereof, and R₃ is a hydrogen, methyl group,or a mixture thereof.

In yet another embodiment, the polyether amine has the genericstructure:

wherein R is any branched or linear alkyl group having from about 1 toabout 20 carbon atoms, preferably about 1 to about 12 carbon atoms, aphenyl group, a cyclic group, an isopropyl group, a propane nitrilegroup, or mixture thereof, and wherein R₁ is —(CH₂)_(a)—, wherein “a”may be a repeating unit ranging from about 1 to about 10, a phenylenegroup, a cyclic group, or mixtures thereof.

Suitable polyether amines include, but are not limited to,methyldiethanolamine; polyoxyalkylenediamines such as,polytetramethylene ether diamines, polyoxypropylenetriamine,polyoxyethylene diamines, and polyoxypropylene diamines; poly(ethyleneoxide capped oxypropylene) ether diamines; propylene oxide-basedtriamines; triethyleneglycoldiamines; trimethylolpropane-basedtriamines; glycerin-based triamines; and mixtures thereof. In oneembodiment, the polyether amine used to form the prepolymer isJeffamine® D2000 (manufactured by Huntsman Corporation of Austin, Tex.).

The molecular weight of the polyether amine for use in the invention mayrange from about 100 to about 5000. In one embodiment, the polyetheramine molecular weight is about 200 or greater, preferably about 230 orgreater. In another embodiment, the molecular weight of the polyetheramine is about 4000 or less. In yet another embodiment, the molecularweight of the polyether amine is about 600 or greater. In still anotherembodiment, the molecular weight of the polyether amine is about 3000 orless. In yet another embodiment, the molecular weight of the polyetheramine is between about 1000 and about 4000, preferably about 1000 toabout 4000, and more preferably is between about 1500 to about 2500.Because lower molecular weight polyether amines may be prone to formingsolid polyureas during prepolymer preparation, a higher molecular weightoligomer, such as Jeffamine® D2000, is preferred.

In addition, the amine-terminated compound may include amine-terminatedpolyesters having the generic structures:

where x is the chain length, i.e., 1 or greater, preferably about 1 toabout 20, R is any branched or linear alkyl group having from about 1 toabout 20 carbon atoms, preferably about 1 to about 12 carbon atoms, aphenyl group, a cyclic group, an isopropyl group, a propane nitrilegroup, or mixture thereof, and R₁ and R₂ are straight or branchedhydrocarbon chains, e.g., alkyl or aryl chains.

Copolymers of polycaprolactone and polyamines may also be used to formthe polyurea prepolymers of the present invention. These copolymersinclude, but are not limited to, bis(2-aminoethyl) ether initiatedpolycaprolactone, 2-(2-aminoethylamino) ethanol, polyoxyethylene diamineinitiated polycaprolactone, propylene diamine initiatedpolycaprolactone, polyoxypropylene diamine initiated polycaprolactone,1,4-butanediamine initiated polycaprolactone, trimethylolpropane-basedtriamine initiated polycaprolactone, neopentyl diamine initiatedpolycaprolactone, hexanediamine initiated polycaprolactone,polytetramethylene ether diamine initiated polycaprolactone, andmixtures thereof. In addition, polycaprolactone polyamines having thefollowing structures may be useful in forming the polyurea prepolymersof the present invention:

where x is the chain length, i.e., 1 or greater, preferably about 1 toabout 20, R is any branched or linear alkyl group having from about 1 toabout 20 carbon atoms, preferably about 1 to about 12 carbon atoms, aphenyl group, a cyclic group, an isopropyl group, a propane nitrilegroup, or mixture thereof, and R₁ is a straight or branched hydrocarbonchain including about 1 to about 20 carbons.

Additional polycaprolactone polyols include those having the followinggeneric structure:

where x is the chain length, i.e., 1 or greater, preferably about 1 toabout 20, R is any branched or linear alkyl group having from about 1 toabout 20 carbon atoms, preferably about 1 to about 12 carbon atoms, aphenyl group, a cyclic group, an isopropyl group, a propane nitrilegroup, or mixture thereof, and R₁ is a straight or branched hydrocarbonchain including about 1 to about 20 carbons.

In another embodiment, the amine-terminated compound may be anamine-terminated polycarbonate having one of the following genericstructures:

where x is the chain length, which preferably ranges from about 1 toabout 20, R is any branched or linear alkyl group having from about 1 toabout 20 carbon atoms, preferably about 1 to about 12 carbon atoms, aphenyl group, a cyclic group, an isopropyl group, a propane nitrilegroup, or mixture thereof, and R₁ is a straight chain hydrocarbon orpredominantly bisphenol A units or derivatives thereof.

Amine-terminated polyamides may also be reacted with the isocyanatecomponent to form the polyurea prepolymer of the present invention.Suitable amine-terminated polyamides include, but are not limited to,those having following structures:

where x is the chain length, i.e., about 1 or greater, R is any branchedor linear alkyl group having from about 1 to about 20 carbon atoms,preferably about 1 to about 12 carbon atoms, a phenyl group, a cyclicgroup, an isopropyl group, a propane nitrile group, or mixture thereof,R₁ is a linear or branched alkyl group having about 1 to about 36 carbonatoms, a phenyl group, or a cyclic group, and R₂ contains a linear orbranched alkyl group having about 1 to about 36 carbon atoms (straightor branched), a phenyl group, a cyclic group, an oxyethylene group, oran oxypropylene group.

Additional amine-terminated compounds that may also be useful in formingthe polyurea prepolymers of the present invention include, but are notlimited to, poly(acrylonitrile-co-butadiene); poly(1,4-butanediol)bis(4-aminobenzoate) in liquid or waxy solid form; linear and branchedpolyethylenimine; low and high molecular weight polyethylenimine havingan average molecular weight of about 500 to about 30,000; poly(propyleneglycol) bis(2-aminopropyl ether) having an average molecular weight ofabout 200 to about 5,000; polytetrahydrofuran bis(3-aminopropyl)terminated having an average molecular weight of about 200 to about2000; and mixtures thereof, all of which are available from Aldrich ofMilwaukee, Wis.

Thus, in one embodiment, the polyurea prepolymer includes apoly(acrylonitrile-co-butadiene) having one of the following structures:

wherein x and y are chain lengths, i.e., greater than about 1, R is anybranched or linear alkyl group having from about 1 to about 20 carbonatoms, preferably about 1 to about 12 carbon atoms, a phenyl group, acyclic group, an isopropyl group, a propane nitrile group, or mixturethereof, R₁ is a hydrogen, methyl group, cyano group, phenyl group, or amixture thereof, and R₂ is a hydrogen, a methyl group, chloride, or amixture thereof. In one embodiment, the y:x ratio is about 82:18 toabout 90:10. In other words, the poly(acrylonitrile-co-butadiene) mayhave from about 10 percent to about 18 percent acrylonitrile by weight.

In another embodiment, the polyurea prepolymer includes apoly(1,4-butanediol) bis(4-aminobenzoate) having one of the followingstructures:

where x and n are chain lengths, i.e., 1 or greater, and n is preferablyabout 1 to about 12, R is any branched or linear alkyl group having fromabout 1 to about 20 carbon atoms, preferably about 1 to about 12 carbonatoms, a phenyl group, a cyclic group, an isopropyl group, a propanenitrile group, or mixture thereof, R₁ is a linear or branched alkylgroup having about 1 to about 36 carbon atoms, a phenyl group, or acyclic group, and R₂ is a hydrogen, a methyl group, or a mixturethereof. In one embodiment, R₁ is phenyl, R₂ is hydrogen, and n is about2.

In yet another embodiment, the polyurea prepolymer includes at least onelinear or branched polyethyleneimine having one of the followingstructures:

wherein x and y are chain lengths, i.e., greater than about 1, R is anybranched or linear alkyl group having from about 1 to about 20 carbonatoms, preferably about 1 to about 12 carbon atoms, a phenyl group, acyclic group, an isopropyl group, a propane nitrile group, or mixturethereof, and R₁ is a hydrogen, methyl group, or a mixture thereof. Inone embodiment, R₁ is hydrogen. In another embodiment, the polyureacomposition includes a mixture of linear and branchedpolyethyleneimines.

In still another embodiment, the polyurea prepolymer of the presentinvention includes a polytetrahydrofuran bis(3-aminopropyl) terminatedcompound having one of the following structures:

where m and n are chain lengths, i.e., 1 or greater, n is preferablyabout 1 to about 12 and m is preferably about 1 to about 6, R is anybranched or linear alkyl group having from about 1 to about 20 carbonatoms, preferably about 1 to about 12 carbon atoms, a phenyl group, acyclic group, an isopropyl group, a propane nitrile group, or mixturethereof, and R₁ and R₂ are hydrogen, methyl groups, or mixtures thereof.In one embodiment, both R₁ and R₂ are hydrogen and both m and n areabout 2.

By using amine-terminated compounds based on a hydrophobic prepolymer,the polyurea prepolymers may provide more water resistance than thosepolyurea prepolymers formed with an amine-terminated hydrophilicprepolymer. Thus, in one embodiment, the amine-terminated compoundincludes hydrophobic backbone, e.g., an unsaturated or saturatedhydrocarbon-based primary or secondary amine-terminated compound. Oneexample of an amine-terminated hydrocarbon is an amine-terminatedpolybutadiene. In another embodiment, the amine-terminated compoundincludes a hydrophobic backbone, and has three functional groups on themolecule.

It is important to note that many amine-terminated compounds may beunsuitable for reaction with the isocyanate because of the rapidreaction between the two components. In general, the reaction rate of analicyclic isocyanate and an alicyclic primary or secondary amine is veryfast. In one embodiment, however, a hindered secondary diamine may besuitable for use in the prepolymer. Without being bound to anyparticular theory, it is believed that an amine with a high level ofstearic hindrance, e.g., a secondary butyl group on the nitrogen atom,has a slower reaction rate than an amine with no hindrance or a lowlevel of hindrance. For example,4,4′-bis-(sec-butylamino)-dicyclohexylmethane (Clearlink® 1000);3,3′-dimethyl-4,4′-bis-(sec-butylamino)-dicyclohexylmethane (Clearlink®3000); 4,4′-bis-(butylamino)-dicyclohexylmethane;3,3′-dimethyl-4,4′-bis-(butylamino)-dicyclohexylmethane;1,4-bis-(sec-butylamino)-cyclohexane;1,2-bis-(sec-butylamino)-cyclohexane;N,N′-dialkylaminodicyclohexylmethane;N,N′-diethylmaleate-2-methyl-pentamethylene diamine (Desmophen® NH1220); N,N′-di(ethylmaleate-amino)dicyclohexylmethane (Desmophen® NH1420); N,N′-di(ethylmaleate-amino)-dimethyldicyclohexylmethane(Desmophen® NH 1520); 1,2-, 1,3-, and 1,4-bis-(sec-butylamino) xylene;1,2-, 1,3-, and 1,4-bis-(sec-butylamino methyl) cyclohexane;3-{[(5-amino-1,3,3-trimethylcyclohexyl)methyl]amino}-propane nitrile;and mixtures thereof may be suitable for use in combination with anisocyanate to form prepolymers according to the invention.

In addition, the use of decelerants, such as aminoalcohols or cycliccarbonates may be use in the compositions of the invention to reduce thespeed of reaction between specific isocyanates and amine-terminatedcompounds. Suitable aminoalcohols for use with the present inventioninclude, but are not limited to, monoethanolamine, monoisopropanolamine,diethanolamine, diisopropanolamine, and mixtures thereof. In addition,alicyclic carbonates, such as ethylene carbonate, propylene carbonate,butylene carbonate, and mixtures thereof, can be used to slow down thereaction. However, once a decelerant is included in the polyureaprepolymer, urethane linkages may be formed from excess isocyanate andhydroxyl groups in the decelerant (depending on the type of decelerantused). As such, the prepolymer is no longer a pure polyurea prepolymer,but instead a prepolymer including both urea and a small amount ofurethane linkages. Such a prepolymer is distinct from a polyureaprepolymer including only an isocyanate and an amine-terminated compoundor a polyurethane prepolymer including only an isocyanate and a polyol.For the sake of clarity, this type of prepolymer will be referred to asa polyurea-polyurethane prepolymer throughout the application.

Likewise, while the amine-terminated compound may also be blended withadditional polyols (as discussed above with respect to the polyurethaneprepolymers), once a polyol is included in the polyurea prepolymer,urethane linkages may be formed, which would result in apolyurea-polyurethane prepolymer as discussed above.

Curing Agents

The prepolymers of the present invention may be cured by crosslinkingthe prepolymers with a single curing agent or a blend of curing agents.Because the compositions of the invention may be castable thermoset orthermoplastic in nature, the prepolymer to curative ratio is important.For example, castable thermoplastic compositions of the inventioninclude linear polymers and are typically formed from curing theprepolymer with a diol or secondary diamine with 1:1 stoichiometry inthe absence of moisture. Thermoset compositions of the invention, on theother hand, are cross-linked polymers and are typically produced fromthe reaction of an isocyanate and a polyol or polyamine cured with aprimary diamine or polyfunctional glycol.

Skilled artisans are aware that the various properties of the golf balland golf ball components, e.g., hardness, may be controlled by adjustingthe ratio of prepolymer to curing agent, which is a function of the NCOcontent of the prepolymer and molecular weight of the curing agent. Forexample, the ratio of a polyurea prepolymer with 6 percent unreacted NCOgroups cured with 1,4-butanediol is 15.6:1, whereas the ratio of thesame prepolymer cured with 4,4′-bis-(sec-butylamino)-dicyclohexylmethane(Clearlink® 1000) is 4.36:1. The ratio of prepolymer to curing agent forthe purposes of this invention is preferably from about 0.5:1 to about16:1. In one embodiment, the equivalent ratio of prepolymer to curingagent may be about 0.7:1.0 to about 1.3:1.0, preferably about 0.9:1 toabout 1.15:1.0. In another embodiment, the prepolymer to curing agentratio is about 1.0:1.0 to about 1.1:1.0. In an alternative embodiment,the ratio of prepolymer to curing agent is about 1.1:0.90, preferablyabout 1.0:0.95.

The curing agent of the invention may include a hydroxy-terminatedcuring agent, an amine-terminated curing agent, or a combinationthereof, the selection of which depends on the desired linkage, i.e.,urethane, urea, or both. Both types of curing agents, i.e.,hydroxy-terminated and amine curatives, may include one or moresaturated, unsaturated, linear, branched, aromatic, and cyclic groups.Additionally, the hydroxy-terminated and amine curatives may include oneor more halogen groups. And, as discussed above, the curing agents ofthe present invention are preferably trifunctional in order to improvethe crosslink density of the composition. The trifunctional compoundsdiscussed earlier in the application are also suitable for use as curingagents.

Suitable hydroxy-terminated curing agents include, but are not limitedto, castor oil, ethylene glycol; diethylene glycol; polyethylene glycol;propylene glycol; 2-methyl-1,3-propanediol; 2-methyl-1,4-butanediol;dipropylene glycol; polypropylene glycol; 1,2-butanediol;1,3-butanediol; 1,4-butanediol; 2,3-butanediol;2,3-dimethyl-2,3-butanediol; cyclohexyldimethylol;N,N,N′N′-tetra-(2-hydroxypropyl)-ethylene diamine; diethylene glycolbis-(aminopropyl) ether; 1,5-pentanediol; 1,6-hexanediol;1,3-bis-(2-hydroxyethoxy) cyclohexane; 1,4-cyclohexyldimethylol;1,3-bis-[2-(2-hydroxyethoxy) ethoxy]cyclohexane;1,3-bis-{2-[2-(2-hydroxyethoxy) ethoxy]ethoxy}cyclohexane;1,3-bis-(2-hydroxyethoxy) benzene; 1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene; 1,3-bis-{2-[2-(2-hydroxyethoxy) ethoxy]ethoxy}benzene;polytetramethylene ether glycol, preferably having a molecular weightranging from about 250 to about 3900; resorcinol-di-(beat-hydroxyethyl)ether and its derivatives; hydroquinone-di-(beta-hydroxyethyl) ether andits derivatives; 1,3-bis-(2-hydroxyethoxy) benzene;1,3-bis-[2-(2-hydroxyethoxy) ethoxy]benzene;N,N-bis(β-hydroxypropyl)aniline; 2-propanol-1,1′-phenylaminobis;2,4,6-tris(N-methyl-N-hydroxymethyl-aminomethyl)phenol;1,2,4-butanetriol; 1,2,6-hexanetriol; trimethylolethane;trimethylolpropane; triethanolamine; triisopropanolamine;pentaerythritol; 1,2,3,4,5,6-hexanehexol; sorbitol; and mixturesthereof. The hydroxy-terminated curing agent may have a molecular weightof at least about 50. In one embodiment, the molecular weight of thehydroxy-terminated curing agent is about 2000 or less.

The saturated hydroxy-terminated curing agents, included in the listabove, are preferred when making a light stable composition. Thosesaturated hydroxy-terminated curing agents include, but are not limitedto, ethylene glycol; diethylene glycol; polyethylene glycol; propyleneglycol; 2-methyl-1,3-propanediol; 2-methyl-1,4-butanediol; dipropyleneglycol; polypropylene glycol; 1,2-butanediol; 1,3-butanediol;1,4-butanediol; 2,3-butanediol; 2,3-dimethyl-2,3-butanediol;cyclohexyldimethylol; N,N,N′,N′-tetra-(2-hydroxypropyl)ethylene diamine;diethylene glycol bis-(aminopropyl) ether; 1,5-pentanediol;1,6-hexanediol; 1,3-bis-(2-hydroxyethoxy) cyclohexane;1,4-cyclohexyldimethylol; 1,3-bis-[2-(2-hydroxyethoxy)ethoxy]cyclohexane; 1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}cyclohexane; 1,2,4-butanetriol; 1,2,6-hexanetriol;trimethyolethane; trimethylolpropane; triethanolamine;triisopropanolamine; pentaerythritol; 1,2,3,4,5,6-hexanehexyl; sorbitol;polytetramethylene ether glycol having molecular weight ranging fromabout 250 to about 3900; and mixtures thereof.

Furthermore, even though polyols used in polyurethane prepolymers aretraditionally long chain and curing agents are traditionally shortchain, any of the polyols discussed above with respect to theprepolymers of the invention are suitable for use as hydroxy-terminatedcuring agents.

Suitable amine-terminated curing agents for use with the presentinvention include, but are not limited to, primary diamine curingagents, secondary diamine curing agents, and mixtures thereof. Inaddition, any of the amine-terminated compounds discussed above withrespect to the prepolymers of the invention are suitable for use as acuring agent. Examples of amine-terminated curing agents contemplatedfor use include, but are not limited to, ethylene diamine; hexamethylenediamine; 1-methyl-2,6-cyclohexyl diamine; 2,2,4- and2,4,4-trimethyl-1,6-hexanediamine;4,4′-bis-(sec-butylamino)-dicyclohexylmethane and derivatives thereof;1,4-bis-(sec-butylamino)-cyclohexane;1,2-bis-(sec-butylamino)cyclohexane; 4,4′-dicyclohexylmethane diamine;1,4-cyclohexane-bis-(methylamine); 1,3-cyclohexane-bis-(methylamine);diethylene glycol bis-(aminopropyl) ether;2-methylpentamethylene-diamine; diaminocyclohexane; diethylene triamine;triethylene tetramine; tetraethylene pentamine; propylene diamine;1,3-diaminopropane; dimethylamino propylamine; diethylamino propylamine;imido-bis-(propylamine); monoethanolamine, diethanolamine;triethanolamine; monoisopropanolamine, diisopropanolamine;isophoronediamine; 4,4′-methylenebis-(2-chloroaniline);3,5-dimethylthio-2,4-toluenediamine;3,5-dimethylthio-2,6-toluenediamine; 3,5-diethylthio-2,4-toluenediamine;3,5-diethylthio-2,6-toluenediamine;4,4′-bis-(sec-butylamino)-diphenylmethane and derivatives thereof;1,4-bis-(sec-butylamino)-benzene; 1,2-bis-(sec-butylamino)-benzene;N,N′-dialkylamino-diphenylmethane;trimethyleneglycol-di-p-aminobenzoate;polytetramethyleneoxide-di-p-aminobenzoate;4,4′-methylenebis-(3-chloro-2,6-diethyleneaniline);4,4′-methylenebis-(2,6-diethylaniline); meta-phenylenediamine;paraphenylenediamine; N,N′-diisopropyl-isophoronediamine (commerciallyavailable from Huntsman Corporation under the tradename Jefflink® 754);polyoxypropylene diamine; propylene oxide-based triamine;3,3′-dimethyl-4,4′-diaminocyclohexylmethane; 1,2-, 1,3-, and1,4-bis-(sec-butylamino) xylene; 1,2-, 1,3-, and 1,4-bis-(sec-butylaminomethyl) cyclohexane; and mixtures thereof. In one embodiment, theamine-terminated curing agent is4,4′-bis-(sec-butylamino)-dicyclohexylmethane. In one embodiment, theamine-terminated curing agent may have a molecular weight of about 64 orgreater. In another embodiment, the molecular weight of the amine-curingagent is about 2000 or less. In addition, any of the amine-terminatedmoieties listed above may be used as curing agents to react with thepolyurea prepolymers.

Of the list above, the saturated amine-terminated curing agents suitablefor use with the present invention include, but are not limited to,ethylene diamine; hexamethylene diamine; 1-methyl-2,6-cyclohexyldiamine; 2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine;4,4′-bis-(sec-butylamino)-dicyclohexylmethane;1,4-bis-(sec-butylamino)-cyclohexane;1,2-bis-(sec-butylamino)-cyclohexane; derivatives of4,4′-bis-(sec-butylamino)-dicyclohexylmethane; 4,4′-dicyclohexylmethanediamine; 1,4-cyclohexane-bis(methylamine);1,3-cyclohexane-bis-(methylamine); diethylene glycol bis-(aminopropyl)ether; 2-methylpentamethylene-diamine; diaminocyclohexane; diethylenetriamine; triethylene tetramine; tetraethylene pentamine; propylenediamine; 1,3-diaminopropane; dimethylamino propylamine; diethylaminopropylamine; imido-bis-(propylamine); monoethanolamine, diethanolamine;triethanolamine; monoisopropanolamine, diisopropanolamine;isophoronediamine; 1,2-, 1,3-, and 1,4-bis-(sec-butylamino) xylene;1,2-, 1,3-, and 1,4-bis-(sec-butylamino methyl) cyclohexane;N,N′-diethylmaleate-2-methylpentamethylene diamine (Desmophen® NH 1220);N,N′-di(ethylmaleate-amino)dicyclohexylmethane (Desmophen® NH 1420);N,N′-di(ethylmaleate-amino)-dimethyldicyclohexylmethane (Desmophen® NH1520); 3-{[(5-amino-1,3,3-trimethylcyclohexyl)methyl]amino}-propanenitrile; and mixtures thereof.

In one aspect of the invention, the curing agent may be part of acurative blend that includes the at least one curing agent and at leastone primary amine, triol, triamine, or combinations thereof. Forexample, if included, the primary diamines are preferably highermolecular weight primary diamines that may be employed to increase thecrosslink density of the compositions of the invention. Suitable primarydiamines for use with the present invention include, but are not limitedto, 4,4′-diaminodicyclohexylmethane,3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, polyoxyethylene diamines,polyoxypropylene diamines, (ethylene oxide-capped)-polyoxypropylenediamines, polytetramethylene ether diamines, and mixtures thereof. Whenpresent in the curative blend, the primary amine, triol, and/or triamineare preferably included in an amount of about 1 percent to about 50percent by weight of the curative blend. In one embodiment, the curativeblend includes about 5 percent to about 40 percent of at least oneprimary amine, triol, and/or triamine.

In another aspect of the invention, the curing agent may be part of amodified curative blend as disclosed in co-pending U.S. patentapplication Ser. No. 10/339,603, filed Jan. 10, 2003, entitled“Polyurethane Compositions for Golf Balls,” which is incorporated byreference herein in its entirety. For example, the curing agent of theinvention may be modified with a freezing point depressing agent tocreate a curative blend with a slower onset of solidification and withstorage stable pigment dispersion. A number of amine-terminated curingagents have relatively high freezing points, e.g., hexamethylene diamine(105.8° F.), diethanolamine (82.4° F.), triethanol amine (69.8° F.),diisopropanolamine (73.4° F.), and triisopropanolamine (111.2° F.). Suchamine-terminated curing agents may be modified with an amine-terminatedfreezing point depressing agent or a mixture of amine-terminatedfreezing point depressing agents. Suitable amine-terminated freezingpoint depressing agents include, but are not limited to, ethylenediamine, 1,3-diaminopropane, dimethylamino propylamine, tetraethylenepentamine, 1,2-propylenediamine, diethylaminopropylamine,2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine,and mixtures thereof. In one embodiment, the modified curative blendincludes at least one trifunctional material.

The freezing point depressing agent is preferably added in an amountsufficient to reduce the freezing point of the curing agent by asuitable amount to prevent loss of pigment dispersion, but not affectthe physical properties of the golf ball. In one embodiment, thefreezing point depressing agent is added to the curing agent in anamount of about 5 percent or greater by weight of the curative blend,i.e., curing agent(s), freezing point depressing agent. In anotherembodiment, the freezing point depressing agent is present in an amountof about 8 percent greater by weight of the curative blend. In stillanother embodiment, the freezing point depressing agent is present in anamount of about 10 percent or greater. In yet another embodiment, thecurative blend includes the freezing point depressing agent in an amountof about 12 percent or greater by weight of the curative blend. Thecurative blend may also include a freezing point depressing agent in anamount of about 14 percent or greater by weight of the curative blend.

In addition, after freezing and subsequent thawing, the modifiedcurative blend preferably has a pigment dispersion of greater than 0 onthe Hegman scale, preferably about 1 or greater, and more preferablyabout 2 or greater. In one embodiment, the modified curative blend aftera freeze/thaw cycle has a pigment dispersion of about 3 or greater onthe Hegman scale. In another embodiment, the modified curative blendafter a freeze and thaw is about 4 or greater on the Hegman scale,preferably about 5 or greater. In still another embodiment, the modifiedcurative blend after a freeze and thaw is about 6 or greater on theHegman scale. In yet another embodiment, the modified curative blendafter freezing and thawing is about 7 or greater on the Hegman scale.

Additives

Additional materials may be added to the compositions of the inventionincluding, but not limited to, coloring agents or dyes, opticalbrighteners, crosslinking agents, whitening agents such as TiO₂ and ZnO,UV absorbers, hindered amine light stabilizers, defoaming agents,processing aids, softening agents, plasticizers, surfactants, impactmodifiers, fillers, reinforcing materials, catalysts, compatibilizers,fragrance components, and other conventional additives. Those ofordinary skill in the art are aware of the purpose of these additivesand the amounts that should be employed to fulfill those purposes.

For example, fillers may be added to the compositions of the inventionto affect rheological and mixing properties, the specific gravity (i.e.,density-modifying fillers), the modulus, the tear strength,reinforcement, and the like. The fillers are generally inorganic, andsuitable fillers include numerous metals, metal oxides and salts, suchas zinc oxide and tin oxide, as well as barium sulfate, zinc sulfate,calcium carbonate, zinc carbonate, barium carbonate, clay, tungsten,tungsten carbide, an array of silicas, regrind (recycled core materialtypically ground to about 30 mesh particle), high-Mooney-viscosityrubber regrind (having a Mooney viscosity of about 55 or greater), andmixtures thereof.

In addition, the compositions of the invention may contain at least onelight stabilizing component. As used herein, light stabilizer may beunderstood to include hindered amine light stabilizers, ultraviolet (UV)absorbers, and antioxidants. While the compositions of the inventionpreferably include only saturated components, which are typicallyresistant to discoloration, they are not immune to deterioration intheir mechanical properties upon weathering. Addition of UV absorbersand light stabilizers to any of the above compositions may help tomaintain the tensile strength, elongation, and color stability. The useof light stabilizing components also may assist in preventing coversurface fractures due to photodegradation. Suitable light stabilizersinclude, but are not limited to, TINUVIN® 292, TINUVIN® 328, TINUVIN®213, TINUVIN® 765, TINUVIN® 770 and TINUVIN® 622. TINUVIN® products areavailable from Ciba Specialty Chemicals of Tarrytown, N.Y. In oneembodiment, the light stabilizer is UV absorber TINUVIN® 328, which isuseful with aromatic compounds. In another embodiment, hindered aminelight stabilizer TINUVIN® 765 is used with aromatic or aliphaticcompounds. In addition, TINUVIN® 292 may also be used with the aromaticor aliphatic compositions of the invention.

Moreover, as discussed above, dyes, as well as optical brighteners andfluorescent pigments may also be included in the golf ball coversproduced with polymers formed according to the present invention. Suchadditional ingredients may be added in any amounts that will achievetheir desired purpose. For example, a white dispersion may used in thecompositions of the invention, preferably in an amount of about 0.5percent to about 10 percent by weight of the composition. In oneembodiment, the composition of the invention includes about 2 percent toabout 8 percent of white dispersion by weight of the composition. Inanother embodiment, the white dispersion is present in the compositionin an amount of about 3 percent to about 6 percent by weight of thecomposition. In still another embodiment, the white dispersion ispresent in the composition in an amount of about 3.5 percent to about 5percent by weight of the composition.

A catalyst may also be employed in the compositions of the invention toincrease or decrease the reaction between the prepolymer and the curingagent for the polyurethane and polyurea compositions of the invention.For example, while the use of a catalyst is usually employed inpolyurethane compositions to increase the rate of reaction, a catalystmay be used with the polyurea system in order to slow down the reactionrate.

As such, with regard to a polyurethane composition of the invention, acatalyst is preferably added in an amount sufficient to catalyze thereaction of the components in the reactive mixture. In one embodiment,the catalyst is present in an amount from about 0.001 percent to about 5percent by weight of the composition. For example, when using a tincatalyst, such as bis-butyltin dilaurate, the catalyst is preferablypresent in an amount from about 0.005 percent to about 1 percent. Inanother embodiment, the catalyst is present in an amount of about 0.05weight percent or greater. In another embodiment, the catalyst ispresent in an amount of about 0.5 weight percent or greater.

Suitable catalysts for use with the polyurethane and polyureacompositions of the invention include, but are not limited to bismuthcatalyst; zinc octoate; stannous octoate; tin catalysts such asbis-butyltin dilaurate (DABCO® T-12 manufactured by Air Products andChemicals, Inc.), bis-butyltin diacetate (DABCO® T-1); stannous octoate(DABCO® T-9); tin (II) chloride, tin (IV) chloride, bis-butyltindimethoxide (FASCAT®-4211), dimethyl-bis[1-oxonedecyl)oxy]stannane(FORMEZ® UL-28), di-n-octyltin bis-isooctyl mercaptoacetate (FORMEZ®UL-29); amine catalysts such as triethylenediamine (DABCO® 33-LV),triethylamine, and tributylamine; organic acids such as oleic acid andacetic acid; delayed catalysts such as POLYCAT® SA-1, POLYCAT® SA-2,POLYCAT®, and the like; and mixtures thereof. In one embodiment, thecatalyst is bis-butyltin dilaurate.

Use of low levels of tin catalysts, typically from about 0 to about 0.04weight percent of the total composition, requires high temperatures toachieve a suitable reaction rate, which may result in degradation of theprepolymer. Increasing the amount of catalysts to unconventional highlevels enables the reduction in process temperatures while retainingcomparable cure stages. Use of the higher catalyst level also allows themixing speeds to be reduced. Thus, in one embodiment, the tin catalystis present in an amount from about 0.01 percent to about 0.55 percent byweight of the composition. In another embodiment, about 0.05 percent toabout 0.4 percent of tin catalyst is present in the composition. In yetanother embodiment, the tin catalyst is present in an amount from about0.1 percent to about 0.25 percent.

Furthermore, some materials used in the compositions of the inventionare odorous in nature or produce odors during reaction with othermaterials or with oxygen. A fragrance or masking component may be addedto the compositions of the invention to eliminate odors.

The fragrance component is preferably added in an amount of about 0.01percent to about 1.5 percent by weight of the composition. In oneembodiment, the fragrance component is added to the composition in anamount of about 0.03 percent to about 1.2 percent by weight of thecomposition. In another embodiment, the fragrance component is added inan amount of about 0.5 percent to about 1 percent by weight of thecomposition. Suitable fragrance components include, but are not limitedto, Long Lasting Fragrance Mask #59672, Long Lasting Fragrance Mask#46064, Long Lasting Fragrance Mask #55248, Non-Descript Fragrance Mask#97779, Fresh and Clean Fragrance Mask #88177, and Garden FreshFragrance Mask #87473, all of which are manufactured by Flavor andFragrance Specialties of Mahwah, N.J. Other non-limiting examples offragrance components that may be added to the compositions of theinvention include benzaldehyde, benzyl benzoate, benzyl propionate,benzyl salicylate, benzyl alcohol, cinnamic aldehydes, natural andessential oils derived from botanical sources, and mixtures thereof.

Methods of Forming

The compositions of the invention may be formed using a variety ofmethods. There are two basic techniques used to process the polyurethaneand polyurea-based elastomers of the present invention: the one-shottechnique and the prepolymer technique. The one-shot technique reactsthe isocyanate, the polyol and/or amine-terminated compound, and thecuring agent in one step, whereas the prepolymer technique requires afirst reaction between the polyol and/or amine-terminated compound andan isocyanate to produce a polyurethane or polyurea prepolymer,respectively, and a subsequent reaction between the prepolymer and acuring agent. Either method may be employed to produce the compositionsof the invention, however, the prepolymer technique is preferred becauseit provides better control of chemical reaction and, consequently,results in more uniform properties for the elastomers.

Acid Functionalization of Compositions

The present invention also contemplates the acid functionalization ofthe compositions of the invention as disclosed in U.S. PatentPublication No. 2003/0153716, which is incorporated by reference hereinin its entirety. Without being bound to any particular theory, it isbelieved that compositions including acid functional moieties or groupshave improved adhesion to other components or layers. The acidfunctional group is preferably based on a sulfonic group (HSO₃),carboxylic group (HCO₂), phosphoric acid group (H₂PO₃), or a combinationthereof. More than one type of acid functional group may be incorporatedinto the polyurea or polyurethane.

In one embodiment, the acid functional polyurea or polyurethane isprepared from a prepolymer having acid functional moieties. The acidgroup(s) may be incorporated onto the isocyanate, polyol component, orcuring agent when making a polyurethane composition. When making apolyurea composition of the invention, the acid group(s) may beincorporated onto the isocyanate, amine-terminated component, or curingagent.

The acid group(s) may also be incorporated during a post-polymerizationreaction, wherein the acid functional group(s) is introduced or attachedto the polyurea or polyurethane. Moreover, the acid functional polyureaor polyurethanes made by way of copolymerization as described above maybe further incorporated with additional acid functional groups throughsuch post-polymerization reactions. Suitable agents to incorporate acidfunctional groups onto the polyurea or polyurethane and methods formaking are described in U.S. Pat. No. 6,207,784, the entire disclosureof which is incorporated by reference herein. One of ordinary skill inthe art would be aware of other ways to prepare the acid functionalpolyurea or polyurethane. For example, a combination of the embodimentsdescribed above may be used as described in U.S. Pat. No. 5,661,207, thedisclosure of which is incorporated by reference in its entirety herein.

Suitable acid functional polyols for use in the polyurethanecompositions of the invention, along with reagents and methods used toderive such acid functional polyols, are disclosed in detail in U.S.Pat. Nos. 5,661,207 and 6,103,822, the disclosures of which areincorporated herein by reference in their entirety. In one embodiment,acid functional polyols for use in a polyurethane prepolymer includescarboxylated, sulfonated, or phosphonated derivatives of polyesterpolyols. Suitable acid functional polyols may have an acid number(calculated by dividing acid equivalent weight to 56,100) of at leastabout 10, preferably from about 20 to about 420, more preferably fromabout 25 to about 150, and most preferably from about 30 to about 75. Inaddition, the hydroxyl number (calculated by dividing hydroxylequivalent number to 56,100) of the polyols may be at least about 10,preferably from about 20 to about 840, and more preferably from about 20to about 175, and most preferably from about 50 to about 150. Thepolyols may also have a hydroxyl functionality (average number ofhydroxyl groups per polyol molecule) of at least about 1.8, preferablyfrom about 2 to about 4.

Suitable acid functional isocyanates include conventional isocyanateshaving an acid functional group that may be formed by reacting anisocyanate and an acid functional group containing compound as describedin U.S. Pat. Nos. 4,956,438 and 5,071,578, the disclosures of which areincorporated herein by reference in their entirety.

The acid functional polyurethanes or polyureas may be partially or fullyneutralized with an organic or an inorganic metal base and/or a tertiaryamine to produce anionic polyurethanes/polyurea ionomers. The base maybe added during preparation of the prepolymer or as a separateneutralization step on the already polymerized acid functionalpolyurethane and polyurea. If these stages occur simultaneously, thebase is preferably present throughout all stages.

Suitable metal bases used for partial or total neutralization mayinclude compounds such as metal oxides, metal hydroxides, metalcarbonates, metal bicarbonates and metal acetates. The metal ions mayinclude, but are not be limited to, Group IA, IB, IIA, IIB, IIIA, IIIB,IVA, IVB, VA, VB, VIIA, VIB, VIIB and VIIIB metal ions. Preferredmetallic ions of such bases include lithium, sodium, potassium,magnesium, zinc, calcium, manganese, aluminum, tungsten, zirconium,titanium and hafnium. The amines are preferably hindered organictertiary amines such as tributylamine, triethylamine, triethylenediamine, dimethyl cetylamine and similar compounds. Primary or secondaryamines may be used, preferably only if the neutralization step takesplace after the polymer is formed, because the amine hydrogen willreadily react with the isocyanate groups thereby interfering with thepolyurea or polyurethane polymerization. One of ordinary skill in theart is aware of additional appropriate chemicals for neutralization.

Composition Blends

The compositions of the invention may be blended with other conventionalmaterials. For example, in one embodiment, the composition containsabout 10 percent to about 90 percent of the composition of theinvention, preferably from about 10 percent to about 75 percent, andcontains about 90 percent to 10 percent, more preferably from about 90percent to about 25 percent other polymers and/or other materials asdescribed below. Unless otherwise stated herein, all percentages aregiven in percent by weight of the total composition of the golf balllayer in question.

Other polymeric materials suitable for blending with the compositions ofthe invention include castable thermoplastics, cationic and anionicurethane ionomers (as disclosed in U.S. Pat. No. 5,692,974) and urethaneepoxies (as disclosed in U.S. Pat. No. 5,908,358), polyurethaneionomers, polyurea ionomers (as disclosed in U.S. Pat. No. 5,484,870),epoxy resins, polyethylenes, polyamides and polyesters, polycarbonates,polyacrylin, siloxanes and epoxy resins or their blends, and mixturesthereof. One of ordinary skill in the art would be well aware of methodsto blend the polymeric materials with the composition of the invention.The disclosures of the above patents are incorporated herein byreference in their entirety.

Crosslink Density

The functionality of the composition components has a significant effecton the potential crosslink density. As used herein, crosslink densityrefers to moles of crosslinked basic units per weight unit of thecrosslinked polymer. For example, a monomer with a functionality of twomeans that monomer can only link to two other reactive sites, whereas amonomer with a functionality of three can link to three other reactivesites. In a system where one out of every 20 molecules is a bifunctionalisocyanate, and 10 of every 20 molecules is a bifunctional amine oralcohol, the crosslink density is 0.05. Therefore, the use of atrifunctional isocyanate in place of a bifunctional isocyanate increasesthe amount of reactive sites and, therefore, increases the crosslinkdensity.

Because the compositions of the invention include at least onetrifunctional component, the compositions of the invention have animproved crosslink density (or crosslink concentration) over that ofmore conventional cover compositions, which, in turn, leads to greaterdimensional stability, increased mechanical strength, and improved heatresistance.

In one embodiment, the crosslink density of the compositions of theinvention is about 0.05 or greater. In another embodiment, the crosslinkdensity of the compositions of the invention is about 0.1 or greater. Instill another embodiment, the crosslink density of the compositions ofthe invention is about 0.2 or greater. In yet another embodiment, thecrosslink density of the compositions of the invention is about 0.5 orgreater. For example, the crosslink density of the compositions of theinvention may be about 0.8 or greater. In another embodiment, thecrosslink density of the compositions of the invention is about 1 orgreater. In still another embodiment, the crosslink density is about 2or greater.

Those of ordinary skill in the art are aware of the number of ways thatcrosslink density can be determined in a polymer network. For example,one method involves the use of Pulsed Nuclear Magnetic Resonance (NMR)spectroscopy. In addition, solvent swelling may be used to determinecrosslink density because the extent of swelling is inverselyproportional to the crosslink density of a network polymer.

As known to those of skill in the art, however, as the crosslink densityincreases in a polymer, there is generally a decrease in the flexibilityof the polymer chains, i.e., the polymer chains are less able to movefreely and rotate in a network. Thus, it is important to achieve acrosslink density that provides dimensional stability, but does not havea negative impact on the flexibility of the material. Without beingbound by any particular theory, it is believed that one way of achievingthis balance is to use high average molecular weight segments betweencrosslinks (M_(c)) so as to allow for a greater number of polymer chainsto become load bearing under strain, which, in turn, results in highertensile strength.

In one embodiment, the segments between crosslinks have an M_(c) ofabout 3000 or greater, preferably about 4000 or greater. In anotherembodiment, the M_(c) is about 5000 or greater. In still anotherembodiment, the M_(c) is about 7000 or greater. In yet anotherembodiment, the M_(c) is about 11,000 or greater. For example, the M_(c)may be about 15,000 or greater. In one embodiment, the M_(c) is about20,000 or greater.

Glass Transition Temperature

As discussed above, the effective chain length between crosslinks(M_(c)) effects the mechanical properties, e.g., elasticity andelongation, of the compositions of the invention. In addition, themechanical properties of a composition also strongly depend on its glasstransition temperature (T_(g)). For example, compositions with lowerT_(g)s are believed to be more resilient. As such, the compositions ofthe invention preferably have a lower glass transition temperature thanthat of a comparable composition does not include a trifunctionalcomponent. In other words, the compositions of the invention preferablyhave glass transition temperatures low enough that play in non-optimaltemperatures does not result in loss of resiliency.

As discussed in the preceding section, a lower crosslink densitygenerally leads to a more flexible polymer composition, i.e., theeffective chain length is high. In fact, the highest flexibility isobtained with non-crosslinked polymers. However, the flexibility of apolymer composition can be enhanced by increasing the linear molecularweight between crosslinks. As such, it is now believed that a highermolecular weight between crosslinks in the compositions of the inventionlead to lower glass transition temperatures because of the increasedflexibility in the individual polymer chains.

It is important to note that T_(g) is distinct from the onset softeningtemperature or melting point of a polymer or composition. In fact, onsetsoftening and melting are transitions that occurs in crystallinepolymers when the polymer chains fall out of their crystal structuresand become a disordered liquid. On the other hand, the glass transitiontemperature is a transition that happens to amorphous polymers, i.e.,polymers whose chains are not arranged in ordered crystals, even thoughthey are in the solid state. However, even crystalline polymers willhave an amorphous portion, e.g., about 40 percent to about 70 percent ofthe polymer, which is why the same polymer can have both a glasstransition temperature and a melting temperature or onset softeningtemperature. One of ordinary skill in the art should be aware of methodsfor determining the T_(g) of a composition. For example, differentialscanning calorimetry will provide the glass transition temperature, thecrystallization temperature, and the melting temperature.

The T_(g) of a composition of the invention is preferably about 68° F.or less. In one embodiment, the T_(g) of a composition of the inventionis about 60° F. or less, preferably about 50° F. or less. For example,the T_(g) of a composition of the invention may be about 40° F. or lessso that golfers in cold climates can continue to play through the winterseason. In another embodiment, the T_(g) of a composition of theinvention is about 32° F. or less. In still another embodiment, theT_(g) of a composition of the invention is about 20° F. or less. In yetanother embodiment, the T_(g) of a composition of the invention is about10° F. or less.

Onset Softening Temperature

The compositions of the invention preferably have a higher onsetsoftening temperature than comparable compositions that do not includetrifunctional components. As used herein, “onset softening temperature”refers to the temperature at which a material begins to soften uponapplication of heat. Thus, in order to have improved heat resistance,the compositions of the invention preferably have a higher onsetsoftening temperature than known compositions.

One indicator of the onset softening temperature is a timed ultravioletexposure test. For example, a control ball component made from a knowncomposition may be tested against a ball component made according to thepresent invention by subjecting the balls to exposure to ultravioletlight for a predetermined number of days, e.g., 5 days, 8 days, etc. Theball component may be observed for wrinkling, melting, or softening overthis time period. The compositions of the invention preferably do notsuffer from wrinkling, melting, and/or softening under ultraviolet lightexposure for at least about 5 days. In one embodiment, no wrinkling,melting, or softening occurs for at least about 8 days. In anotherembodiment, the compositions of the invention do not wrinkle, melt, orsoften upon exposure to ultraviolet for at least about 10 days or more.

In one embodiment, the compositions of the invention have an onsetsoftening temperature of about 90° F. or greater, preferably about 100°F. or greater. In another embodiment, the onset softening temperature ofthe compositions of the invention is about 110° F. or greater. In stillanother embodiment, the compositions of the invention have an onsetsoftening temperature of about 120° F. or greater. In yet anotherembodiment, the onset softening temperature is about 150° F. or greater.

Changes in COR

Golf ball components formed from compositions of the inventionpreferably exhibit appreciable changes in COR as the temperaturedecreases, generally through the range of about 70° F. to about 20° F.This differs from conventional components in that the COR ofconventional components is usually static when the temperaturedecreases. In one embodiment, a golf ball component formed according tothe invention exhibits an increase in COR of about 7 percent or greaterwhen the temperature decreases by about 15° F. or more. In anotherembodiment, the COR increases by about 15 percent or greater when thetemperature decreases by about 30 degrees or more. In yet anotherembodiment, the COR increases by about 20 percent or greater when thetemperature decreases by about 40 degrees or greater.

The tangent delta (tan δ) is inversely related to the changes in the CORfor components formed from compositions of the invention. The tan δ isdefined as the ratio of the loss modulus to the storage modulus. Thus,the higher the tan δ, the less resilient (or deader) the material. Assuch, when the compositions of the invention have an increase in COR asthe temperature decreases through the range of about 70° F. to about 20°F., the tan δ decreases. In one embodiment, the tan δ decreases by atleast about 0.1 with a decrease in temperature of about 15° F. or more.In another embodiment, the tan δ decreases by at least about 0.2 with adecrease in temperature of about 30° F. or more. In yet anotherembodiment, the tan δ decreases by at least about 0.25 when thetemperature decreases by about 40° F. or more.

In other words, the tan δ of the compositions of the inventionpreferably decreases by about 30 percent or more with a decrease intemperature of about 15° F. or more. In one embodiment, the tan δdecreases by about 40 percent or greater when the temperature decreasesby about 20° F. or more. In another embodiment, when the temperaturedecreases by about 30° F. or greater, the tan δ decreases by about 50percent or more, preferably about 60 percent or greater. In stillanother embodiment, the tan δ of the compositions of the inventionpreferably decreases by about 70 percent or more with a decrease intemperature of about 30° F. or more.

In contrast to the golf ball component formed from the compositions ofthe invention, golf balls having a cover formed of the compositions ofthe invention, i.e., golf balls typically having at least a core and acover, have little to no appreciable change in COR when temperature isdecreased through the range of about 70° F. to about 5° F. For example,when the temperature is decreased by about 15 degrees or greater, theCOR of a multi-component golf ball formed from a composition of theinvention preferably drops by about 5 percent or less. In oneembodiment, the COR changes by about 3 percent or less with atemperature change of about 15 degrees or greater. In anotherembodiment, the COR changes by about 2 percent or less with atemperature change of about 15 degrees or greater. This differs fromconventional balls with polybutadiene cores in that conventional ballsexhibit changes in COR as the temperature decreases.

When the temperature drops more dramatically, such as a change of about45 degrees or greater, the COR of a component formed from a compositionof the invention preferably changes by about 5 percent or less. In oneembodiment, the COR changes by about 4 percent or less with a change intemperature of about 45 degrees or greater. More preferably, the CORchanges by about 3 percent or less with a change in temperature of about45 degrees or greater. In another embodiment, the change in COR is about2 percent or less with a change in temperature of about 45 degrees orgreater. In still another embodiment, the COR has no appreciable changewhen the temperature changes by about 45 degrees or more. As usedherein, “no appreciable change” refers to a COR value that changes byless than about 1 percent over a given temperature range.

When the temperature drops even more dramatically, such as a change intemperature of about 60 degrees or greater, the COR of a componentformed from a composition of the invention preferably changes by about10 percent or less. In one embodiment, the COR changes by about 7percent or less with a change in temperature of about 60 degrees orgreater. More preferably, the COR changes by about 5 percent or lesswith a change in temperature of about 60 degrees or greater. In anotherembodiment, the change in COR is about 3 percent or less with a changein temperature of about 60 degrees or greater. In still anotherembodiment, the COR has no appreciable change when the temperaturechanges by about 60 degrees or more.

Golf Ball Construction

The compositions of the present invention may be used with any type ofball construction. For example, one-piece, two-piece, three-piece, andfour-piece golf ball designs are contemplated by the present invention.In addition, golf balls having double cores, intermediate layer(s),and/or double covers are also useful with the present invention. Asknown to those of ordinary skill in the art, the type of golf ballconstructed, i.e., double core, double cover, and the like, depends onthe type of performance desired of the ball. As used herein, the term“layer” includes any generally spherical portion of a golf ball, i.e., agolf ball core or center, an intermediate layer, and/or a golf ballcover. As used herein, the term “inner layer” refers to any golf balllayer beneath the outermost structural layer of the golf ball. As usedherein, “structural layer” does not include a coating layer, top coat,paint layer, or the like. As used herein, the term “multilayer” means atleast two layers.

In one embodiment, a golf ball 2 according to the invention (as shown inFIG. 1) includes a core 4 and a cover 6, wherein the at least one ofcore 4 and cover 6 incorporates at least one layer including thecomposition of the invention. Similarly, FIG. 2 illustrates a golf ballaccording to the invention incorporating an intermediate layer. Golfball 8 includes a core 10, a cover 14, and an intermediate layer 12disposed between the core 10 and cover 14. Any of the core 10,intermediate layer 12, or cover 14 may incorporate at least one layerthat includes the compositions of the invention. FIG. 3 illustrates amultilayer golf ball 16 according to the invention including a largecore 18, an outer core layer, intermediate layer, or inner cover layer20, and an outer cover layer 22. Any of the core 18, outer core layer,intermediate layer, or inner cover layer 20, and outer cover layer 22may include the composition of the invention. FIG. 4 shows a four-piecegolf ball 24 according to the invention including a core 26, an outercore layer or intermediate layer 28, an inner cover layer 30, and anouter cover layer 32. Any of the core 26, outer core layer orintermediate layer 28, inner cover layer 30, and outer cover layer 32may include the composition of the invention.

Other non-limiting examples of suitable types of ball constructions thatmay be used with the present invention include those described in U.S.Pat. Nos. 6,056,842, 5,688,191, 5,713,801, 5,803,831, 5,885,172,5,919,100, 5,965,669, 5,981,654, 5,981,658, and 6,149,535, as well as inPublication Nos. US2001/0009310 A1, US2002/0025862, US2002/0028885,US2002/0151380. The entire disclosures of these patents and publishedpatent applications are incorporated by reference herein. For example,in Publication No. US2002/015380, a golf ball having three or more coverlayers is disclosed, of which any of the layers of the ball may beformed using the compositions of the invention. In addition, thecompositions of the invention are contemplated for use in layers of thegradated hardness multilayer golf balls disclosed in U.S. PatentPublication No. 2001/0005699, which is incorporated by reference hereinin its entirety.

As discussed, the golf balls of the invention include at least onestructural layer that includes compositions of the invention. Inaddition, as discussed in more detail below, the golf balls of theinvention may include core layers, intermediate layers, or cover layersformed from materials known to those of skill in the art. These examplesare not exhaustive, as skilled artisans would be aware that a variety ofmaterials might be used to produce a golf ball of the invention withdesired performance properties.

Core Layer(s)

The cores of the golf balls formed according to the invention may besolid, semi-solid, hollow, fluid-filled, or powder filled, but arepreferably solid and formed with the compositions of the invention. Asused herein, the term “core” means the innermost portion of a golf ball,and may include one or more layers. For example, U.S. Pat. Nos.6,180,040 and 6,180,722 disclose methods of preparing dual core golfballs. The entire disclosures of these patents are incorporated byreference herein. The term “semi-solid” as used herein refers to apaste, a gel, or the like. The cores of the golf balls of the inventionmay be spherical, cubical, pyramid-shaped, geodesic, or anythree-dimensional, symmetrical shape.

While the cores of the invention may be formed with compositions of theinvention, conventional materials may also be used to form the cores.Suitable core materials include, but are not limited to, thermosetmaterials, such as rubber, styrene butadiene, polybutadiene, isoprene,polyisoprene, trans-isoprene, and polyurethane, and thermoplasticmaterials, such as conventional ionomer resins, polyamides, polyesters,and polyurethane. In one embodiment, at least one layer of the core isformed from a polybutadiene reaction product, such as the reactionproducts disclosed in U.S. Patent Publication No. 2003/0119989, theentire disclosure of which is incorporated by reference herein.

The core may also include one or more wound layers (surrounding a fluidor solid center) including at least one tensioned elastomeric materialwound about the center. In one embodiment, the tensioned elastomericmaterial includes natural or synthetic elastomers or blends thereof, inwhich the synthetic elastomer preferably includes LYCRA. The tensionedelastomeric material may also incorporate conventional polyisoprene, apolybutadiene reaction product, a polyurea composition, and/or solventspun polyethers urea, as disclosed in co-pending U.S. Patent PublicationNos. 2003/0119989, 2003/0096936 and U.S. Pat. No. 6,149,535, which areincorporated in their entirety by reference herein.

In another aspect of the invention, the golf balls of the inventioninclude a thin, highly filled core layer, such as the ones disclosed inU.S. Pat. No. 6,494,795, which is incorporated by reference herein inits entirety. A thin, highly filled core layer allows the weight or massof the golf ball to be allocated radially relative to the centroid,thereby dictating the moment of inertia of the ball. When the weight isallocated radially toward the centroid, the moment of inertia isdecreased, and when the weight is allocated outward away from thecentroid, the moment of inertia is increased.

Intermediate Layer(s)

As used herein, “intermediate layer” includes any layer between theinnermost layer of the golf ball and the outermost layer of the golfball. Therefore, intermediate layers may also be referred to as outercore layers, inner cover layers, and the like. When the golf ball of thepresent invention includes an intermediate layer, this layer may beformed from the compositions of the invention.

The intermediate layer may also be formed of conventional materialsknown to those of ordinary skill in the art, including various thermosetand thermoplastic materials, as well as blends thereof. For example, theintermediate layer may be formed, at least in part, from one or morehomopolymeric or copolymeric materials, such as vinyl resins, low andhigh acid ionomer resins, polyolefins, polyurethanes, polyureas,polyamides, acrylic resins, olefinic thermoplastic rubbers, blockcopolymers of styrene and butadiene, isoprene or ethylene-butylenerubber, copoly(ether-amide), polyphenylene oxide resins, thermoplasticpolyesters, ethylene, propylene, 1-butene or 1-hexene based homopolymersor copolymers, and the like.

The intermediate layer may also be formed from highly neutralizedpolymers such as those disclosed U.S. Patent Publication Nos.2001/0018375 and 2001/0019971, which are incorporated herein in theirentirety by express reference thereto; grafted and non-graftedmetallocene catalyzed polyolefins and polyamides, polyamide/ionomerblends, and polyamide/nonionomer blends, such as those disclosed in U.S.Patent Publication No. 2003/0078348, which is incorporated by referenceherein in its entirety; among other polymers. Examples of other suitableintermediate layer materials include blends of some of the abovematerials, such as those disclosed in U.S. Pat. No. 5,688,181, theentire disclosure of which is incorporated by reference herein.

The intermediate layer may also be a moisture barrier layer, such as theones described in U.S. Pat. No. 5,820,488, which is incorporated in itsentirety by reference herein.

Cover Layer(s)

The cover provides the interface between the ball and a club. As usedherein, the term “cover” means the outermost portion of a golf ball. Acover typically includes at least one layer and may contain indentationssuch as dimples and/or ridges. Paints and/or laminates are typicallydisposed about the cover to protect the golf ball during use thereof.The cover may include a plurality of layers, e.g., an inner cover layerdisposed about a golf ball center and an outer cover layer formedthereon.

Inner and/or outer cover layers may be formed from the compositions ofthe invention. Alternatively, both the inner and/or outer cover layersof golf balls of the present invention may be formed of polyurea,polyurethane, or mixtures thereof, as disclosed in co-pending U.S.Patent Publication Nos. 2003/0096936 and 2003/0212240. The entiredisclosures of these publications are incorporated by reference herein.

In addition, cover layers may also be formed of one or morehomopolymeric or copolymeric materials, such as vinyl resins,polyolefins, conventional polyurethanes and polyureas, such as the onesdisclosed in U.S. Pat. Nos. 5,334,673, and 5,484,870, polyamides,acrylic resins and blends of these resins with poly vinyl chloride,elastomers, and the like, thermoplastic urethanes, olefinicthermoplastic rubbers, block copolymers of styrene and butadiene,polyphenylene oxide resins or blends of polyphenylene oxide with highimpact polystyrene, thermoplastic polyesters, ethylene, propylene,1-butene or 1-hexane based homopolymers or copolymers includingfunctional monomers, methyl acrylate, methyl methacrylate homopolymersand copolymers, low acid ionomers, high acid ionomers, highlyneutralized ionomers, alloys, and mixtures thereof. The cover may alsobe at least partially formed from a polybutadiene reaction product asdisclosed in U.S. Patent Publication No. 2003/0119989.

As discussed above with respect to the core of the golf balls of theinvention, the use of a thin, highly filled layer allows the weight ormass of the golf ball to be allocated radially relative to the centroid,thereby dictating the moment of inertia of the ball. This concept istranslatable to the cover layers of a golf ball. Thus, the inner coverlayer may be a thin, dense layer so as to form a high moment of inertiaball. In this aspect of the invention, the inner cover layer preferablyhas a specific gravity of greater than 1.2, more preferably more than1.5, even more preferably more than 1.8, and most preferably more than2.0. Suitable materials for the thin, dense layer include any materialthat meets the specific gravity stated above. For example, this thin,highly filled inner cover layer may be formed of the radiation-curablecompositions of the invention, adjusting for the requisite specificgravity. Alternatively, the inner cover layer may be formed fromepoxies, styrenated polyesters, polyurethanes or polyureas, liquidPBR's, silicones, silicate gels, agar gels, and the like.

Additional materials may be included in the core, intermediate layer,and/or cover layer compositions outlined above. For example, catalysts,coloring agents, optical brighteners, crosslinking agents, whiteningagents such as TiO₂ and ZnO, UV absorbers, hindered amine lightstabilizers, defoaming agents, processing aids, surfactants, and otherconventional additives may be added to the cover layer compositions ofthe invention. In addition, antioxidants, stabilizers, softening agents,plasticizers, including internal and external plasticizers, impactmodifiers, foaming agents, density-adjusting fillers, reinforcingmaterials, and compatibilizers may also be added to any of the coverlayer compositions. Those of ordinary skill in the art should be awareof the requisite amount for each type of additive to realize thebenefits of that particular additive.

Methods for Forming Golf Ball Components

The golf balls of the invention may be formed using a variety ofapplication techniques such as compression molding, flip molding,injection molding, retractable pin injection molding, reaction injectionmolding (RIM), liquid injection molding (LIM), casting, vacuum forming,powder coating, flow coating, spin coating, dipping, spraying, and thelike depending on the materials used for a specific component. Forexample, the compositions of the invention are particular useful incasting applications. Thus, golf ball components including thecompositions of the invention may be formed by casting.

One skilled in the art, however, would appreciate that the moldingmethod used may be determined at least partially by the properties ofthe composition. For example, casting, RIM, or LIM may be preferred whenthe material is thermoset, whereas compression molding or injectionmolding may be preferred for thermoplastic compositions. Compressionmolding, however, may also be used for thermoset inner ball materials.For example, when cores are formed from a thermoset material,compression molding is a particularly suitable method of forming thecore, whereas when the cores are formed of a thermoplastic material, thecores may be injection molded. In addition, the intermediate layer mayalso be formed from using any suitable method known to those of ordinaryskill in the art. For instance, an intermediate layer may be formed byblow molding and covered with a dimpled cover layer formed by injectionmolding, compression molding, casting, vacuum forming, powder coating,and the like.

Any inner layer of the golf balls of the invention may be surfacetreated prior to cover formation to further increase the adhesionbetween the outer surface of the inner ball and the cover. In addition,the outermost cover of the golf balls of the invention may be surfacetreated prior to application of any coating layer. Such surfacetreatment may include mechanically or chemically abrading the outersurface of the subassembly. Additionally, the inner ball may besubjected to corona discharge, plasma treatment, and/or silane dippingprior to forming the cover around it. Other layers of the ball, e.g.,the core, also may be surface treated. Examples of these and othersurface treatment techniques can be found in U.S. Pat. No. 6,315,915,which is incorporated by reference in its entirety.

The methods discussed herein and other manufacturing methods for formingthe golf ball components of the present invention are also disclosed inU.S. Pat. Nos. 6,207,784 and 5,484,870, the disclosures of which areincorporated herein by reference in their entirety.

Dimples

The golf balls of the invention are preferably designed with certainflight characteristics in mind. The use of various dimple patterns andprofiles provides a relatively effective way to modify the aerodynamiccharacteristics of a golf ball. As such, the manner in which the dimplesare arranged on the surface of the ball can be by any available method.For instance, the ball may have an icosahedron-based pattern, such asdescribed in U.S. Pat. No. 4,560,168, or an octahedral-based dimplepatterns as described in U.S. Pat. No. 4,960,281. Alternatively, thedimple pattern can be arranged according to phyllotactic patterns, suchas described in U.S. Pat. No. 6,338,684, or a tubular lattice pattern,such as the one disclosed in U.S. Pat. No. 6,290,615, the disclosures ofwhich are incorporated herein in their entirety.

Dimple patterns may also be based on Archimedean patterns including atruncated octahedron, a great rhombcuboctahedron, a truncateddodecahedron, and a great rhombicosidodecahedron, wherein the patternhas a non-linear parting line, as disclosed in U.S. patent applicationSer. No. 10/078,417, which is incorporated in its entirety by referenceherein. The golf balls of the present invention may also be covered withnon-circular shaped dimples, i.e., amorphous shaped dimples, asdisclosed in U.S. Pat. No. 6,409,615, which is incorporated in itsentirety by reference herein.

Dimple patterns that provide a high percentage of surface coverage arepreferred, and are well known in the art. For example, U.S. Pat. Nos.5,562,552, 5,575,477, 5,957,787, 5,249,804, and 4,925,193 disclosegeometric patterns for positioning dimples on a golf ball. In oneembodiment, the golf balls of the invention have a dimple coverage ofthe surface area of the cover of at least about 60 percent, preferablyat least about 65 percent, and more preferably at least 70 percent orgreater. Dimple patterns having even higher dimple coverage values mayalso be used with the present invention. Thus, the golf balls of thepresent invention may have a dimple coverage of at least about 75percent or greater, about 80 percent or greater, or even about 85percent or greater.

The golf balls of the present invention may also have a plurality ofpyramidal projections disposed on the intermediate layer of the ball, asdisclosed in U.S. Pat. No. 6,383,092, which is incorporated in itsentirety by reference herein. The plurality of pyramidal projections onthe golf ball may cover between about 20 percent to about 80 of thesurface of the intermediate layer. In an alternative embodiment, thegolf ball may have a non-planar parting line allowing for some of theplurality of pyramidal projections to be disposed about the equator.

Several additional non-limiting examples of dimple patterns with varyingsizes of dimples are also provided in U.S. Pat. Nos. 6,358,161 and6,213,898, the entire disclosures of which are incorporated by referenceherein.

The total number of dimples on the ball, or dimple count, may varydepending such factors as the sizes of the dimples and the patternselected. In general, the total number of dimples on the ball preferablyis between about 100 to about 1000 dimples, although one skilled in theart would recognize that differing dimple counts within this range cansignificantly alter the flight performance of the ball. In oneembodiment, the dimple count is about 380 dimples or greater, but morepreferably is about 400 dimples or greater, and even more preferably isabout 420 dimples or greater. In one embodiment, the dimple count on theball is about 422 dimples. In some cases, it may be desirable to havefewer dimples on the ball. Thus, one embodiment of the present inventionhas a dimple count of about 380 dimples or less, and more preferably isabout 350 dimples or less.

Dimple profiles revolving a catenary curve about its symmetrical axismay increase aerodynamic efficiency, provide a convenient way to alterthe dimples to adjust ball performance without changing the dimplepattern, and result in uniformly increased flight distance for golfersof all swing speeds. Thus, catenary curve dimple profiles, as disclosedin U.S. Patent Publication No. 2003/0114255, which is incorporated inits entirety by reference herein, is contemplated for use with the golfballs of the present invention.

Golf Ball Post-Processing

The golf balls of the present invention may be painted, coated, orsurface treated for further benefits. For example, a golf ball of theinvention may be treated with a base resin paint composition or thecover composition may contain certain additives to achieve a desiredcolor characteristic. In one embodiment, the golf ball cover compositioncontains a fluorescent whitening agent to provide improved weatherresistance and brightness. An example of such a fluorescent whiteningagent is disclosed in U.S. Patent Publication No. 2002/0082358, which isincorporated by reference herein in its entirety.

Protective and decorative coating materials, as well as methods ofapplying such materials to the surface of a golf ball cover are wellknown in the golf ball art. Generally, such coating materials compriseurethanes, urethane hybrids, epoxies, polyesters and acrylics. Ifdesired, more than one coating layer can be used. The coating layer(s)may be applied by any suitable method known to those of ordinary skillin the art. For example, the coating layer(s) may be applied to the golfball cover by an in-mold coating process, such as described in U.S. Pat.No. 5,849,168, which is incorporated in its entirety by referenceherein. The coating layer may have a thickness of about 0.004 inches orless, more preferably about 0.002 inches or less.

In addition, the golf balls of the invention may be painted or coatedwith an ultraviolet curable/treatable ink, by using the methods andmaterials disclosed in U.S. Pat. Nos. 6,500,495, 6,248,804, and6,099,415, the entire disclosures of which are incorporated by referenceherein.

Furthermore, trademarks or other indicia may be stamped, i.e.,pad-printed, on the outer surface of the ball cover, and the stampedouter surface is then treated with at least one clear coat to give theball a glossy finish and protect the indicia stamped on the cover.

The golf balls of the invention may also be subjected to dyesublimation, wherein at least one golf ball component is subjected to atleast one sublimating ink that migrates at a depth into the outersurface and forms an indicia. The at least one sublimating inkpreferably includes at least one of an azo dye, a nitroarylamine dye, oran anthraquinone dye. U.S. Patent Publication No. 2003/0106442, theentire disclosure of which is incorporated by reference herein.

Laser marking of a selected surface portion of a golf ball causing thelaser light-irradiated portion to change color is also contemplated foruse with the present invention. U.S. Pat. Nos. 5,248,878 and 6,075,223generally disclose such methods, the entire disclosures of which areincorporated by reference herein. In addition, the golf balls may besubjected to ablation, i.e., directing a beam of laser radiation onto aportion of the cover, irradiating the cover portion, wherein theirradiated cover portion is ablated to form a detectable mark, whereinno significant discoloration of the cover portion results therefrom.Ablation is discussed in U.S. Pat. No. 6,462,303, which is incorporatedin its entirety by reference herein.

Golf Ball Properties

The properties such as hardness, modulus, core diameter, and layerthickness of the golf balls of the present invention have been found toeffect play characteristics such as spin, initial velocity and feel ofthe present golf balls. For example, the flexural and/or tensile modulusof the intermediate layer are believed to have an effect on the “feel”of the golf balls of the present invention. It should be understood thatthe ranges herein are meant to be intermixed with each other, i.e., thelow end of one range may be combined with a high end of another range.

Component Dimensions

Dimensions of golf ball components, i.e., thickness and diameter, mayvary depending on the desired properties. For the purposes of theinvention, any layer thickness may be employed. Non-limiting examples ofthe various embodiments outlined above are provided here with respect tolayer dimensions.

The present invention relates to golf balls of any size. While USGAspecifications limit the size of a competition golf ball to more than1.68 inches in diameter, golf balls of any size can be used for leisuregolf play. The preferred diameter of the golf balls is from about 1.68inches to about 1.8 inches. The more preferred diameter is from about1.68 inches to about 1.76 inches. A diameter of from about 1.68 inchesto about 1.74 inches is most preferred, however diameters anywhere inthe range of from 1.7 to about 1.95 inches can be used. Preferably, theoverall diameter of the core and all intermediate layers is about 80percent to about 98 percent of the overall diameter of the finishedball.

The core may have a diameter ranging from about 0.09 inches to about1.65 inches. In one embodiment, the diameter of the core of the presentinvention is about 1.2 inches to about 1.630 inches. In anotherembodiment, the diameter of the core is about 1.3 inches to about 1.6inches, preferably from about 1.39 inches to about 1.6 inches, and morepreferably from about 1.5 inches to about 1.6 inches. In yet anotherembodiment, the core has a diameter of about 1.55 inches to about 1.65inches.

The core of the golf ball may also be extremely large in relation to therest of the ball. For example, in one embodiment, the core makes upabout 90 percent to about 98 percent of the ball, preferably about 94percent to about 96 percent of the ball. In this embodiment, thediameter of the core is preferably about 1.54 inches or greater,preferably about 1.55 inches or greater. In one embodiment, the corediameter is about 1.59 inches or greater. In another embodiment, thediameter of the core is about 1.64 inches or less.

When the core includes an inner core layer and an outer core layer, theinner core layer is preferably about 0.9 inches or greater and the outercore layer preferably has a thickness of about 0.1 inches or greater. Inone embodiment, the inner core layer has a diameter from about 0.09inches to about 1.2 inches and the outer core layer has a thickness fromabout 0.1 inches to about 0.8 inches. In yet another embodiment, theinner core layer diameter is from about 0.095 inches to about 1.1 inchesand the outer core layer has a thickness of about 0.20 inches to about0.03 inches.

The cover typically has a thickness to provide sufficient strength, goodperformance characteristics, and durability. The thickness of the outercover layer may be from about 0.005 inches to about 0.100 inches,preferably about 0.007 inches to about 0.035 inches. In one embodiment,the cover thickness is from about 0.02 inches to about 0.35 inches. Inanother embodiment, the cover preferably has a thickness of about 0.02inches to about 0.12 inches, preferably about 0.1 inches or less, morepreferably about 0.07 inches or less. In yet another embodiment, theouter cover has a thickness from about 0.02 inches to about 0.07 inches.In still another embodiment, the cover thickness is about 0.05 inches orless, preferably from about 0.02 inches to about 0.05 inches. Forexample, the outer cover layer may be between about 0.02 inches andabout 0.045 inches, preferably about 0.025 inches to about 0.04 inchesthick. In one embodiment, the outer cover layer is about 0.03 inchesthick.

The range of thicknesses for an intermediate layer of a golf ball islarge because of the vast possibilities when using an intermediatelayer, i.e., as an outer core layer, an inner cover layer, a woundlayer, a moisture/vapor barrier layer. When used in a golf ball of theinvention, the intermediate layer, or inner cover layer, may have athickness about 0.3 inches or less. In one embodiment, the thickness ofthe intermediate layer is from about 0.002 inches to about 0.1 inches,preferably about 0.01 inches or greater. In one embodiment, thethickness of the intermediate layer is about 0.09 inches or less,preferably about 0.06 inches or less. In another embodiment, theintermediate layer thickness is about 0.05 inches or less, morepreferably about 0.01 inches to about 0.045 inches. In one embodiment,the intermediate layer, thickness is about 0.02 inches to about 0.04inches. In another embodiment, the intermediate layer thickness is fromabout 0.025 inches to about 0.035 inches. In yet another embodiment, thethickness of the intermediate layer is about 0.035 inches thick. Instill another embodiment, the inner cover layer is from about 0.03inches to about 0.035 inches thick. Varying combinations of these rangesof thickness for the intermediate and outer cover layers may be used incombination with other embodiments described herein.

The ratio of the thickness of the intermediate layer to the outer coverlayer is preferably about 10 or less, preferably from about 3 or less.In another embodiment, the ratio of the thickness of the intermediatelayer to the outer cover layer is about 1 or less.

Hardness

Most golf balls consist of layers having different hardnesses, e.g.,hardness gradients, to achieve desired performance characteristics. Thepresent invention contemplates golf balls having hardness gradientsbetween layers, as well as those golf balls with layers having the samehardness.

It should be understood, especially to one of ordinary skill in the art,that there is a fundamental difference between “material hardness” and“hardness, as measured directly on a golf ball.” Material hardness isdefined by the procedure set forth in ASTM-D2240 and generally involvesmeasuring the hardness of a flat “slab” or “button” formed of thematerial of which the hardness is to be measured. Hardness, whenmeasured directly on a golf ball (or other spherical surface) is acompletely different measurement and, therefore, results in a differenthardness value. This difference results from a number of factorsincluding, but not limited to, ball construction (i.e., core type,number of core and/or cover layers, etc.), ball (or sphere) diameter,and the material composition of adjacent layers. It should also beunderstood that the two measurement techniques are not linearly relatedand, therefore, one hardness value cannot easily be correlated to theother.

The cores of the present invention may have varying hardnesses dependingon the particular golf ball construction. In one embodiment, the corehardness is at least about 15 Shore A, preferably about 30 Shore A, asmeasured on a formed sphere. In another embodiment, the core has ahardness of about 50 Shore A to about 90 Shore D. In yet anotherembodiment, the hardness of the core is about 80 Shore D or less.Preferably, the core has a hardness about 30 to about 65 Shore D, andmore preferably, the core has a hardness about 35 to about 60 Shore D.

The intermediate layer(s) of the present invention may also vary inhardness depending on the specific construction of the ball. In oneembodiment, the hardness of the intermediate layer is about 30 Shore Dor greater. In another embodiment, the hardness of the intermediatelayer is about 90 Shore D or less, preferably about 80 Shore D or less,and more preferably about 70 Shore D or less. In yet another embodiment,the hardness of the intermediate layer is about 50 Shore D or greater,preferably about 55 Shore D or greater. In one embodiment, theintermediate layer hardness is from about 55 Shore D to about 65 ShoreD. The intermediate layer may also be about 65 Shore D or greater.

When the intermediate layer is intended to be harder than the corelayer, the ratio of the intermediate layer hardness to the core hardnesspreferably about 2 or less. In one embodiment, the ratio is about 1.8 orless. In yet another embodiment, the ratio is about 1.3 or less.

As with the core and intermediate layers, the cover hardness may varydepending on the construction and desired characteristics of the golfball. The ratio of cover hardness to inner ball hardness is a primaryvariable used to control the aerodynamics of a ball and, in particular,the spin of a ball. In general, the harder the inner ball, the greaterthe driver spin and the softer the cover, the greater the driver spin.

For example, when the intermediate layer is intended to be the hardestpoint in the ball, e.g., about 50 Shore D to about 75 Shore D, the covermaterial may have a hardness of about 20 Shore D or greater, preferablyabout 25 Shore D or greater, and more preferably about 30 Shore D orgreater, as measured on the slab. In another embodiment, the coveritself has a hardness of about 30 Shore D or greater. In particular, thecover may be from about 30 Shore D to about 70 Shore D. In oneembodiment, the cover has a hardness of about 40 Shore D to about 65Shore D, and in another embodiment, about 40 Shore to about 55 Shore D.In another aspect of the invention, the cover has a hardness less thanabout 45 Shore D, preferably less than about 40 Shore D, and morepreferably about 25 Shore D to about 40 Shore D. In one embodiment, thecover has a hardness from about 30 Shore D to about 40 Shore D.

In this embodiment when the outer cover layer is softer than theintermediate layer or inner cover layer, the ratio of the Shore Dhardness of the outer cover material to the intermediate layer materialis about 0.8 or less, preferably about 0.75 or less, and more preferablyabout 0.7 or less. In another embodiment, the ratio is about 0.5 orless, preferably about 0.45 or less.

In yet another embodiment, the ratio is about 0.1 or less when the coverand intermediate layer materials have hardnesses that are substantiallythe same. When the hardness differential between the cover layer and theintermediate layer is not intended to be as significant, the cover mayhave a hardness of about 55 Shore D to about 65 Shore D. In thisembodiment, the ratio of the Shore D hardness of the outer cover to theintermediate layer is about 1.0 or less, preferably about 0.9 or less.

In another embodiment, the cover layer is harder than the intermediatelayer. In this design, the ratio of Shore D hardness of the cover layerto the intermediate layer is about 1.33 or less, preferably from about1.14 or less.

In addition, the present invention also contemplates the compositions ofthe invention being used in a golf ball with multiple cover layershaving essentially the same hardness, wherein at least one of the layershas been modified in some way to alter a property that affects theperformance of the ball. Such ball constructions are disclosed inco-pending U.S. patent application Ser. No. 10/167,744, filed Jun. 13,2002, entitled “Golf Ball with Multiple Cover Layers,” the entiredisclosure of which is incorporated by reference herein.

Compression

Compression values are dependent on the diameter of the component beingmeasured. Atti compression is typically used to measure the compressionof a golf ball. As used herein, the terms “Atti compression” or“compression” are defined as the deflection of an object or materialrelative to the deflection of a calibrated spring, as measured with anAtti Compression Gauge, that is commercially available from AttiEngineering Corp. of Union City, N.J.

The Atti compression of the core, or portion of the core, of golf ballsprepared according to the invention is preferably less than about 80,more preferably less than about 75. In another embodiment, the corecompression is from about 40 to about 80, preferably from about 50 toabout 70. In yet another embodiment, the core compression is preferablybelow about 50, and more preferably below about 25. In an alternative,low compression embodiment, the core has a compression less than about20, more preferably less than about 10, and most preferably, 0. As knownto those of ordinary skill in the art, however, the cores generatedaccording to the present invention may be below the measurement of theAtti Compression Gauge.

In one embodiment, golf balls of the invention preferably have an Atticompression of about 55 or greater, preferably from about 60 to about120. In another embodiment, the Atti compression of the golf balls ofthe invention is at least about 40, preferably from about 50 to 120, andmore preferably from about 60 to 100. In yet another embodiment, thecompression of the golf balls of the invention is about 75 or greaterand about 95 or less. For example, a preferred golf ball of theinvention may have a compression from about 80 to about 95.

Initial Velocity and COR

There is currently no USGA limit on the COR of a golf ball, but theinitial velocity of the golf ball cannot exceed 250±5 feet/second(ft/s). Thus, in one embodiment, the initial velocity is about 245 ft/sor greater and about 255 ft/s or greater. In another embodiment, theinitial velocity is about 250 ft/s or greater. In one embodiment, theinitial velocity is about 253 ft/s to about 254 ft/s. In yet anotherembodiment, the initial velocity is about 255 ft/s. While the currentrules on initial velocity require that golf ball manufacturers staywithin the limit, one of ordinary skill in the art would appreciate thatthe golf ball of the invention would readily convert into a golf ballwith initial velocity outside of this range. For example, a golf ball ofthe invention may be designed to have an initial velocity of about 220ft/s or greater, preferably about 225 ft/s or greater.

As a result, of the initial velocity limitation set forth by the USGA,the goal is to maximize COR without violating the 255 ft/s limit. TheCOR of a ball is measured by taking the ratio of the outbound or reboundvelocity to the incoming or inbound velocity. In a one-piece solid golfball, the COR will depend on a variety of characteristics of the ball,including its composition and hardness. For a given composition, CORwill generally increase as hardness is increased. In a two-piece solidgolf ball, e.g., a core and a cover, one of the purposes of the cover isto produce a gain in COR over that of the core. When the contribution ofthe core to high COR is substantial, a lesser contribution is requiredfrom the cover. Similarly, when the cover contributes substantially tohigh COR of the ball, a lesser contribution is needed from the core.

The present invention contemplates golf balls having CORs from about0.700 to about 0.850 at an inbound velocity of about 125 ft/sec. In oneembodiment, the COR is about 0.750 or greater, preferably about 0.780 orgreater. In another embodiment, the ball has a COR of about 0.800 orgreater. In yet another embodiment, the COR of the balls of theinvention is about 0.800 to about 0.815.

Spin Rate

As known to those of ordinary skill in the art, the spin rate of a golfball will vary depending on the golf ball construction. In a multilayerball, e.g., a core, an intermediate layer, and a cover, wherein thecover is formed from the compositions of the invention, the spin rate ofthe ball off a driver (“driver spin rate”) may be 1500 rpm or greater.In one embodiment, the driver spin rate is about 2000 rpm to about 3500rpm. In another embodiment, the driver spin rate is about 2200 rpm toabout 3400 rpm. In still another embodiment, the driver spin rate may beless than about 1500 rpm.

Two-piece balls made according to the invention may also have driverspin rates of 1500 rpm and greater. In one embodiment, the driver spinrate is about 2000 rpm to about 3300 rpm. Wound balls made according tothe invention preferably have similar spin rates.

Methods of determining the spin rate should be well understood by thoseof ordinary skill in the art. Examples of methods for determining thespin rate are disclosed in U.S. Pat. Nos. 6,500,073, 6,488,591,6,286,364, and 6,241,622, which are incorporated by reference herein intheir entirety.

Flexural Modulus

Accordingly, it is preferable that the golf balls of the presentinvention have an intermediate layer with a flexural modulus of about500 psi to about 500,000 psi according to ASTM D-6272-98. Morepreferably, the flexural modulus of the intermediate layer is about1,000 psi to about 250,000 psi. Most preferably, the flexural modulus ofthe intermediate layer is about 2,000 psi to about 200,000 psi.

The flexural modulus of the cover layer is preferably about 2,000 psi orgreater, and more preferably about 5,000 psi or greater. In oneembodiment, the flexural modulus of the cover is from about 10,000 psito about 150,000 psi. More preferably, the flexural modulus of the coverlayer is about 15,000 psi to about 120,000 psi. Most preferably, theflexural modulus of the cover layer is about 18,000 psi to about 110,000psi. In another embodiment, the flexural modulus of the cover layer isabout 100,000 psi or less, preferably about 80,000 or less, and morepreferably about 70,000 psi or less. For example, the flexural modulusof the cover layer may be from about 10,000 psi to about 70,000 psi,from about 12,000 psi to about 60,000 psi, or from about 14,000 psi toabout 50,000 psi.

In one embodiment, when the cover layer has a hardness of about 50 ShoreD to about 60 Shore D, the cover layer preferably has a flexural modulusof about 55,000 psi to about 65,000 psi.

In one embodiment, the ratio of the flexural modulus of the intermediatelayer to the cover layer is about 0.003 to about 50. In anotherembodiment, the ratio of the flexural modulus of the intermediate layerto the cover layer is about 0.006 to about 4.5. In yet anotherembodiment, the ratio of the flexural modulus of the intermediate layerto the cover layer is about 0.11 to about 4.5.

In one embodiment, the compositions of the invention are used in a golfball with multiple cover layers having essentially the same hardness,but differences in flexural moduli. In this aspect of the invention, thedifference between the flexural moduli of the two cover layers ispreferably about 5,000 psi or less. In another embodiment, thedifference in flexural moduli is about 500 psi or greater. In yetanother embodiment, the difference in the flexural moduli between thetwo cover layers, wherein at least one is reinforced is about 500 psi toabout 10,000 psi, preferably from about 500 psi to about 5,000 psi. Inone embodiment; the difference in flexural moduli between the two coverlayers formed of unreinforced or unmodified materials is about 1,000 psito about 2,500 psi.

Specific Gravity

The specific gravity of a cover or intermediate layer is preferably atleast about 0.7. In one embodiment, the specific gravity of theintermediate layer or cover is about 0.8 or greater, preferably about0.9 or greater. For example, in one embodiment, the golf ball has anintermediate layer with a specific gravity of about 0.9 or greater and acover having a specific gravity of about 0.95 or greater. In anotherembodiment, the intermediate layer or cover has a specific gravity ofabout 1.00 or greater. In yet another embodiment, the specific gravityof the intermediate layer or cover is about 1.05 or greater, preferablyabout 1.10 or greater.

The core may have a specific gravity of about 1.00 or greater,preferably 1.05 or greater. For example, a golf ball of the inventionmay have a core with a specific gravity of about 1.10 or greater and acover with a specific gravity of about 0.95 or greater.

EXAMPLES

The following non-limiting examples are merely illustrative of thepreferred embodiments of the present invention, and are not to beconstrued as limiting the invention, the scope of which is defined bythe appended claims. Parts are by weight unless otherwise indicated.

Example 1 Resiliency of Unitary Ball Formed with Compositions of theInvention

Unitary golf ball components were formed according to the followingformulations:

PRESENT INVENTION CONTROL Isocyanate¹   1 eq. Prepolymer⁵   1 eq.Curative Blend Curative Blend Polycaprolactone triol² 0.80 eq. Secondarydiamine⁶ 0.95 eq. Polyester polyol³ 0.15 eq. White Dispersion⁴ 3.5%White Dispersion⁴ 3.5% ¹Vestanat T 6040 Isocyanate (a blend ofisophorone diisocyanate and isocyanurate trimer of isophoronediisocyanate), manufactured by Degussa Corporation. ²Tone 0305,manufactured by Dow Chemical Company. ³Oxyester T 1136, manufactured byDegussa Corporation. ⁴HCC-19584 White Dispersion, manufactured by ThePolyOne Corporation. ⁵S28850 Prepolymer, manufactured by PPG Industries.⁶Clearlink 1000 (4,4′-bis-(sec-butylamino)-dicyclohexylmethane),manufactured by Dorf Ketal Chemicals India PVT, Ltd.

As shown in FIG. 5, the unitary ball, i.e., a golf ball component,molded from a composition of the present invention exhibits appreciablechanges in COR with decreased temperature. In particular, the COR of thepresent invention unitary ball is 0.606 at about 67° F. and 0.751 at 20°F. In contrast, the unitary ball molded with a composition that does notinclude a trifunctional material according to the present inventionexhibits a slight decrease in COR with a decrease in temperature (COR of0.633 at 67° F. and 0.631 at 20° F.).

Example 2 Resiliency of Dual Cover Ball Formed with Compositions of theInvention

Golf balls were made with a core, a 1.62-inch inner ionomer casing andan outer cover formed according to the formulations in Example 1. Asshown in FIG. 6, the golf ball having a cover made from a composition ofthe present invention exhibits less of a drop in COR when thetemperature drops. In particular, as the temperature drops from 72° F.to 5° F., the COR of the ball drops from 0.804 to 0.763, about 5percent. In contrast, the golf ball made with the control cover exhibitsa drop in COR from 0.807 to 0.729 as the temperature drops from 72° F.to 5° F., which is greater than about 9 percent.

Example 3 Heat Resistance of Golf Balls Made According to the Invention

Golf balls having covers made with the compositions of the presentinvention were compared to golf balls having covers made without theincorporation of a trifunctional material. The formulations of the covercompositions are as follows:

Formulations Prepolymer Curing Agent Additive Control 1 1 eq. polyurea0.95 eq. secondary 3.5% white prepolymer¹ @ diamine³ dispersion⁴ 6.32%NCO Present Invention 1 eq. polyurea 0.95 eq. secondary 3.5% white Aprepolymer¹ with diamine³ dispersion⁴ 10% isocyanate trimer ofhexamethylene diisocyanate² @ 7.95% NCO Present Invention 1 eq. polyurea0.95 eq. secondary 3.5% white B prepolymer¹ with diamine³ dispersion⁴ 7%isocyanate trimer of hexamethylene diisocyanate² @ 6.35% NCO ¹Polyureaprepolymer includes 4,4-dicyclohexylmethane diisocyanate (H₁₂MDI andJeffamine D 2000 (a polyether amine manufactured by HuntsmanCorporation). ²Desmodur N-3300 (an isocyanurate trimer of hexamethylenediisocyanate), manufactured by Bayer Corporation. ³Clearlink 1000(4,4′-bis-(sec-butylamino)-dicyclohexylmethane), manufactured by DorfKetal Chemicals India PVT, Ltd. ⁴HCC-19584 White Dispersion,manufactured by The PolyOne Corporation.

The golf balls were then subjected to ultraviolet exposure for eightdays. As shown in Table 1, the golf balls made with a trifunctionalmaterial according to the present invention, in this case 7% or 10%isocyanate trimer of hexamethylene diisocyanate, exhibited greater heatresistance as compared to the control balls.

TABLE 1 Ultraviolet Exposure UV Exposure 5 Days 8 Days Control 1Moderate wrinkling Severe wrinkling of cover of cover Present InventionA No change No change Present Invention B No change No change

Example 4 Heat Resistance of Golf Balls Made According to the Invention

Golf balls having covers made with the compositions of the presentinvention were compared to golf balls having covers made without theincorporation of a trifunctional material. The formulations of the covercompositions are as follows:

Formulations Prepolymer Curing Agent Additive Control 2 1 eq. polyurea0.95 eq. amine- 3.5% white prepolymer¹ @ terminated curing dispersion⁴6.32% NCO agent³ Present Invention C 1 eq. polyurea 0.95 eq. amine- 3.5%white prepolymer¹ with terminated curing dispersion⁴ 10% isocyanateagent³ trimer of hexamethylene diisocyanate² @ 7.25% NCO ¹Polyureaprepolymer includes 4,4-dicyclohexylmethane diisocyanate (H₁₂MDI andJeffamine D 2000 (a polyether amine manufactured by HuntsmanCorporation). ²Desmodur N-3300 (an isocyanurate trimer of hexamethylenediisocyanate), manufactured by Bayer Corporation. ³Jefflink 754(N,N′-diisopropyl-isophoronediamine), commercially available fromHuntsman Corporation. ⁴HCC-19584 White Dispersion, manufactured by ThePolyOne Corporation.

The golf balls were then subjected to ultraviolet exposure for eightdays. As shown in Table 2, the golf balls made with a trifunctionalmaterial according to the present invention, in this case 10% isocyanatetrimer of hexamethylene diisocyanate, exhibited much greater heatresistance as compared to the control balls. In particular, the controlgolf balls exhibited severe wrinkling and melting when observed after 5days of UV exposure, whereas the golf balls made according to thepresent invention exhibited no signs of wrinkling after 8 days of UVexposure.

TABLE 2 Ultraviolet Exposure UV Exposure 5 Days 8 Days Control 2 Severewrinkling and/or Severe wrinkling and/or melting of cover melting ofcover Present Invention C No change No change

Example 5 Resiliency of Compositions Made According to the Invention

The compositions of the invention were subjected to Dynamic MechanicalAnalysis (DMA) in order to discern the tan δ (loss modulus/storagemodulus) of the material, which is indicative of the resiliency of thematerial, i.e., the higher the tan δ, the less resilient the material.Compositions were made are follows:

Formulations Prepolymer Curative 1 Curative 2 Control 3 1 eq. polyurea0.95 eq. secondary — prepolymer¹ @ diamine³ 10% NCO Present 1 eq.Isocyanate² 0.80 eq. 0.15 eq. polyester Invention D @ 29.6% NCOpolycaprolactone polyol⁴ triol³ ¹Polyurea prepolymer includes4,4-dicyclohexylmethane diisocyanate (H₁₂MDI and Jeffamine D 2000 (apolyether amine manufactured by Huntsman Corporation). ²Vestanat T 6040Isocyanate (a blend of isophorone diisocyanate and isocyanurate trimerof isophorone diisocyanate), manufactured by Degussa Corporation. ³Tone0305, manufactured by Dow Chemical Company. ⁴Oxyester T 1136,manufactured by Degussa Corporation.

For DMA, each sample was cut to approximately 17 mm×12 mm×1 mm and runin a single cantilever mode. The samples were then equilabrated at −120°C. and then heated to 150° C. at a rate of 2° C./min. As shown in FIG. 7(the invention composition), the tan δ decreases as the temperaturedecreases at least in the range of about 70° F. to about 20° F. Incontrast, the tan δ of the control composition (FIG. 8) actuallyincreases as the temperature decreases from about 70° F. to about 20° F.

The invention described and claimed herein is not to be limited in scopeby the specific embodiments herein disclosed, since these embodimentsare intended as illustrations of several aspects of the invention. Anyequivalent embodiments are intended to be within the scope of thisinvention. For example, the compositions of the invention may also beused in golf equipment such as putter inserts, golf club heads andportions thereof, golf shoe portions, and golf bag portions. Indeed,various modifications of the invention in addition to those shown anddescribed herein will become apparent to those skilled in the art fromthe foregoing description. Such modifications are also intended to fallwithin the scope of the appended claims. All patents and patentapplications cited in the foregoing text are expressly incorporateherein by reference in their entirety.

1. A golf ball comprising at least one layer formed from a compositioncomprising: a polyurea prepolymer comprising the reaction product of anisocyanurate trimer and an amine-terminated component; and at least onetrifunctional curing agent selected from the group consisting ofethylene oxide-based triamines, propylene oxide-based triamines,trimethylolpropane-based triamines, N-(2-aminoethyl)-1,3-propylenediamines, and mixtures thereof, wherein the coefficient of restitutionchanges by about 5 percent or less with a corresponding temperaturedecrease of 15° F. or more, and wherein the composition has an averagemolecular weight between crosslinks of about 3000 or greater.
 2. Thegolf ball of claim 1, wherein the coefficient of restitution changes byabout 3 percent or less with a corresponding temperature decrease ofabout 45° F. or more.
 3. The golf ball of claim 1, wherein thecoefficient of restitution has no appreciable change with acorresponding temperature decrease of about 60° F. or more.
 4. The golfball of claim 1, wherein the golf ball comprises a core and a cover, andwherein the cover is formed of the composition.
 5. The golf ball ofclaim 4, wherein the cover comprises at least two layers.
 6. The golfball of claim 1, wherein the isocyanurate trimer is selected from thegroup consisting of an isocyanurate trimer of hexamethylenediisocyanate, an isocyanurate trimer of toluene diisocyanate, anisocyanurate trimer of isophorone diisocyanate, a blend of isophoronediisocyanate and an isocyanurate trimer of isophorone diisocyanate, andmixtures thereof.
 7. The golf ball of claim 1, wherein the curing agentis selected from the group consisting of ethylene oxide-based triamines,propylene oxide-based triamines, and mixtures thereof.
 8. The golf ballof claim 1, wherein the composition is thermoset.
 9. The golf ball ofclaim 1, wherein the amine-terminated component comprises at least threefunctional groups, and wherein the amine-terminated component isselected from the group consisting of ethylene oxide-based triamines,propylene oxide-based triamines, trimethylolpropane-based triamines,N-(2-aminoethyl)-1,3-propylene diamines.
 10. A golf ball comprising acomponent formed from a composition comprising: a polyurea prepolymercomprising the reaction product of an isocyanurate trimer and anamine-terminated component; and at least one trifunctional curing agentselected from the group consisting of ethylene oxide-based triamines,propylene oxide-based triamines, trimethylolpropane-based triamines,N-(2-aminoethyl)-1,3-propylene diamines, and mixtures thereof, whereinthe component has a COR profile that exhibits an increase as temperaturedecreases from about 70° F. to about 20° F., and wherein the compositionhas an average molecular weight between crosslinks of about 3000 orgreater.
 11. The golf ball component of claim 10, wherein the COR of thegolf ball increases by about 7 percent or more with a correspondingtemperature decrease of about 15° F. or greater.
 12. The golf ballcomponent of claim 10, wherein the COR of the golf ball increases byabout 15 percent or more with a corresponding temperature decrease ofabout 30° F. or greater.
 13. The golf ball component of claim 10,wherein the tan δ of the component decreases by about 40 percent orgreater when the temperature decreases by about 20° F. or more.
 14. Thegolf ball of claim 10, wherein the curing agent is selected from thegroup consisting of ethylene oxide-based triamines, propyleneoxide-based triamines, and mixtures thereof.
 15. A composition for golfballs comprising: a polyurea prepolymer comprising an isocyanuratetrimer and an amine-terminated compound; and a trifunctional curingagent selected from the group consisting of ethylene oxide-basedtriamines, propylene oxide-based triamines, trimethylolpropane-basedtriamines, N-(2-aminoethyl)-1,3-propylene diamines, and mixturesthereof, and wherein the composition has an average molecular weightbetween crosslinks of about 3000 or greater.
 16. The chemicalcomposition of claim 15, wherein the composition has a COR profile thatexhibits an increase as temperature decreases from about 70° F. to about20° F.
 17. The chemical composition of claim 15, wherein the compositionhas a tan δ profile that exhibits a decrease as temperature decreasesfrom about 70° F. to about 20° F.
 18. The golf ball of claim 15, whereinthe curing agent is selected from the group consisting of ethyleneoxide-based triamines, propylene oxide-based triamines, and mixturesthereof.